Aligner device

Abstract

An aligner device 1 is provided with a motor 12, a rotating device 11, a control device 13, and a sensor 14. The motor 12 generates a rotational driving force. The rotating device 11 rotates with a wafer 30 supported thereon, due to the rotational driving force generated by the motor 12. The control device 13 controls the rotation of the rotating device 11 to perform a process of aligning the rotational phase of the wafer 30 with a predetermined value. The sensor 14 irradiates an edge of the wafer 30 with a plurality of light beams having different directions of propagation, and receives light beams to detect a defect in the edge of the wafer 30.

Description

Technical Field

[0001] This application mainly relates to an aligner device equipped with a sensor for detecting defects on a wafer.

Background Art

[0002] Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-299419) discloses a multi-function wafer aligner. The multi-function wafer aligner performs centering correction of a wafer, alignment of the wafer, and detection of damage to the wafer. The multi-function wafer aligner uses a light-emitting sensor and a light-receiving sensor to detect damage to the wafer. The light-emitting sensors are arranged side by side on the lower side of the wafer and irradiate light upward. The light-receiving sensors are arranged side by side at positions facing the side surfaces of the wafer and receive the light reflected by the wafer from the light irradiated by the light-emitting sensors. Since the portions where defects occur on the wafer have depressions or the like, the reflection directions of light are different. Thus, defects on the wafer can be detected based on the positions where the light-receiving sensors receive the light.

[0003] Patent Document 2 (International Publication No. 2019 / 165484) discloses a device for inspecting a wafer.\ This device has a light-emitting part and a detection part arranged so as to sandwich the wafer. The light-emitting part irradiates laser light from a plurality of positions toward the edge of the wafer. The detection part receives the light reflected or scattered by the edge of the wafer from the laser light. Based on the detection result of the detection part, defects on the wafer can be detected with high precision.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The multifunction wafer aligner described in Patent Document 1 cannot detect wafer defects unless there are large dents or other imperfections on the wafer. Furthermore, because the multifunction wafer aligner of Patent Document 1 irradiates light perpendicular to the wafer surface, it is difficult to detect fine particles on the wafer surface. The apparatus of Patent Document 2 only inspects wafers, so the wafers inspected by the apparatus of Patent Document 2 must be transported back to the aligner apparatus. As a result, the processing time for wafers is increased.

[0005] This application has been filed in view of the above circumstances, and its main purpose is to provide an aligner device that can detect defects in wafers with high accuracy and shorten the time required for wafer inspection and alignment. [Means for solving the problem]

[0006] The problem that this application aims to solve is as described above, and next, the means for solving this problem and their effects will be explained.

[0007] From the perspective of this application, an aligner device having the following configuration is provided: The aligner device comprises a motor, a rotating device, a control device, and a sensor. The motor generates a rotational driving force. The rotating device rotates with the wafer supported by the rotational driving force generated by the motor. The control device controls the rotation of the rotating device to adjust the rotational phase of the wafer to a predetermined value. The sensor detects defects on the wafer edge by irradiating the wafer edge with a plurality of lights traveling in different directions and receiving the light.

[0008] By detecting defects at the wafer edges using the method described above, inspection can be performed at multiple locations on the wafer, enabling highly accurate detection of wafer defects. Furthermore, since the aligner device detects wafer defects as well as alignment, the time required for wafer inspection and alignment can be reduced. [Effects of the Invention]

[0009] According to this application, wafer defects can be detected with high accuracy, and the time required for wafer inspection and alignment can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1] A perspective view of the aligner device according to the first embodiment. [Figure 2] A side view showing the internal configuration of the sensor. [Figure 3] A flowchart illustrating the processes performed by the control unit. [Figure 4] A perspective view of the aligner device according to the second embodiment. [Modes for carrying out the invention]

[0011] Next, embodiments of this application will be described with reference to the drawings. Figure 1 is a perspective view of the aligner device 1 of the first embodiment.

[0012] The aligner device 1 shown in Figure 1 is placed in a workspace such as a cleanroom. Wafers 30 are transported to the aligner device 1 by a robot (not shown).

[0013] The robot is, for example, a SCARA-type horizontal articulated robot. SCARA is an abbreviation for Selective Compliance Assembly Robot Arm. The wafer 30 is a thin, circular, plate-shaped semiconductor wafer. The wafer 30 may be a glass wafer instead of a semiconductor wafer.

[0014] Aligner device 1 is a device that performs alignment on wafer 30. Alignment is the process of acquiring the rotational phase of wafer 30 and adjusting the rotational phase of wafer 30 to a predetermined value. The rotational phase of wafer 30 is the orientation of wafer 30 that changes as wafer 30 rotates.

[0015] In the following description, the two circular surfaces of the disc-shaped wafer 30 are referred to as main surfaces 31, and the surface connecting the two main surfaces 31 is referred to as a side surface 32. Furthermore, the radial ends of the main surfaces 31 and the side surfaces 32 of the wafer 30 are collectively referred to as the edge of the wafer 30.

[0016] A notch 33 is formed on the edge of the wafer 30. The notch 33 indicates the crystal orientation of the semiconductor. If an orientation flat is formed on the wafer 30 instead of a notch 33, the aligner device 1 may be configured to detect the orientation flat. Alternatively, the aligner device 1 may be configured to acquire the deviation of the center position of the wafer 30 relative to a reference point, in addition to the rotational phase of the wafer 30.

[0017] The aligner device 1 comprises a rotating device 11, a motor 12, a control device 13, a sensor 14, and a communication device 16.

[0018] The rotating device 11 is a disc-shaped turntable. A robot places the wafer 30 on the rotating device 11. The rotating device 11 supports the wafer 30 by placing it on the device. The surface on which the wafer 30 is placed faces vertically. The rotating device 11 is rotatably supported on a workbench or the like. The shape of the rotating device 11 is not limited to a disc. For example, the rotating device 11 may be a rectangular plate. Alternatively, the rotating device 11 may be configured to grip the sides of the wafer 30 and support the wafer 30.

[0019] The motor 12 generates rotational driving force. The rotational driving force generated by the motor 12 is transmitted to the rotating device 11. As a result, the rotating device 11 rotates with the vertical direction as its center of rotation. Consequently, the rotational phase of the wafer 30 can be changed.

[0020] The motor 12 is controlled by the control device 13. The control device 13 includes an arithmetic unit such as a CPU and a storage device such as an HDD, an SSD, or a flash memory. The arithmetic unit controls the aligner device 1 by executing a program stored in the storage device. The control device 13 may control both the robot and the aligner device 1, or may control only the aligner device 1.

[0021] The rotating device 11 is provided with an encoder (not shown). The detection result of the encoder is transmitted to the control device 13. Thereby, the control device 13 can grasp the rotation phase of the rotating device 11 (that is, the rotation phase of the wafer 30).

[0022] The sensor 14 inspects the wafer 30 placed on the rotating device 11. The sensor 14 includes a housing 21, a light projecting unit 22, and a light receiving unit 23.

[0023] The housing 21 is a box-shaped member that houses the members constituting the sensor 14. The housing 21 is substantially U-shaped and has a first portion 21a and a second portion 21b that face each other with a gap therebetween. An inspection space 21c is formed between the first portion 21a and the second portion 21b. The edge of the wafer 30 supported by the rotating device 11 passes through the inspection space 21c. Thereby, by rotating the rotating device 11 once, the edge of the wafer 30 can be inspected over the entire circumference.

[0024] As shown in FIG. 2, a plurality of light projecting units 22 (specifically, three light projecting units 22) and a light receiving unit 23 are arranged on the first portion 21a. Similarly, a plurality of light projecting units 22 (specifically, three light projecting units 22) and a light receiving unit 23 are arranged on the second portion 21b.

[0025] The light-emitting unit 22 is a laser generator, laser diode, or SLD (superluminescent diode), etc. Therefore, the light (laser light) emitted by the light-emitting unit 22 is directional and has a narrower spectral width compared to the light emitted by the LED. Each light-emitting unit 22 emits light toward the edge of the wafer 30. The optical axis of the light emitted by the light-emitting unit 22 is in contact with the wafer 30. Since the positions of the multiple light-emitting units 22 are different, the direction of propagation of the light emitted by each light-emitting unit 22 is different. Furthermore, the position of the contact point between the optical axis of the light and the wafer 30 is different depending on the light-emitting unit 22.

[0026] The light receiving unit 23 receives the light emitted by the light transmitting unit 22, generates a current signal (or a voltage signal converted therefrom) corresponding to the amount of light received, and outputs it to the control device 13. The light from the light transmitting unit 22 located in the first section 21a is received by the light receiving unit 23 located in the second section 21b. Similarly, the light from the light transmitting unit 22 located in the second section 21b is received by the light receiving unit 23 located in the first section 21a.

[0027] The control device 13 can distinguish which light-emitting unit 22 emitted the current signal input from the light-receiving unit 23. Specifically, the light-receiving unit 23 includes multiple photodiodes, each of which is positioned in a location that coincides with the direction of light propagation from the light-emitting unit 22. This allows the control device 13 to identify which light-emitting unit 22 emitted the current signal, depending on the photodiode that output the current signal. Alternatively, the light-receiving unit 23 may consist of only one photodiode. In this case, the light-emitting unit 22 emits light according to a predetermined schedule, and the light-receiving unit 23 receives the light. The control device 13 can then identify which light-emitting unit 22 emitted the current signal, based on the time the current signal was input and the schedule.

[0028] The light emitted by the light-emitting unit 22 is received by the light-receiving unit 23 after being affected by the surface of the edge of the wafer 30 (for example, after being diffracted at the surface). Therefore, if a defect exists on the surface of the edge of the wafer 30, the light received by the light-receiving unit 23 changes. The control device 13 can determine whether or not a defect exists on the surface of the edge of the wafer 30 based on the current signal input from the light-receiving unit 23. As described above, the position of the contact point between the optical axis of the light emitted by the light-emitting unit 22 and the wafer 30 differs depending on the light-emitting unit 22. Therefore, in this embodiment, defects can be inspected at multiple locations on the edge of the wafer 30.

[0029] Sensor 14 can detect a variety of defects. For example, Sensor 14 can detect that the wafer 30 is warped, that the side surface 32 has irregularities and an inappropriate shape, that the amount of fine particles is greater than a predetermined value, that the diameter of the wafer is inappropriate, and that the concentricity of multiple bonded wafers is inappropriate (in the case of a bonded wafer). In particular, when light is irradiated perpendicularly to the wafer surface as in Patent Document 1, it is difficult to detect fine particles present on the wafer, but by irradiating light at an angle to the surface of the wafer 30 as in this embodiment, it is possible to detect fine particles present on the wafer 30. Also, if the shape of the side surface 32 of the wafer 30 is inappropriate, or if the amount of fine particles present on the side surface 32 is greater than a predetermined value, there is a possibility that similar defects have occurred on the main surface 31 of the wafer 30. Therefore, if there is this type of defect on the side surface 32 of the wafer 30, the control device 13 determines that there is a high probability that the main surface 31 of the wafer 30 also has the same type of defect.

[0030] Furthermore, although not a defect in the wafer 30, the sensor 14 can also detect whether a notch 33 or orientation flat is formed on the wafer 30 in the inspection space 21c. The shapes of the notch 33 and orientation flat are predetermined. Moreover, the shape and size of the notch 33 and orientation flat are completely different from those of typical defects. Therefore, by pre-storing (learning) the current signal output by the light receiving unit 23 when a notch 33 or orientation flat is present in the control device 13, it is possible to distinguish whether a defect exists in the wafer 30 or whether a notch 33 or orientation flat exists in the wafer 30. This allows the control device 13 to perform defect inspection and alignment of the wafer 30 simultaneously.

[0031] The communication device 16 is connected to or built into the control device 13. The communication device 16 can communicate with an external device 40. The external device 40 is a higher-level device than the aligner device 1 and controls the aligner device 1 and other wafer processing devices together. The communication device 16 is, for example, a communication module and includes a connector for wired communication or an antenna for wireless communication.

[0032] Next, with reference to Figure 3, the control performed by the control device 13 regarding the inspection and alignment of defects in the wafer 30 will be described.

[0033] First, the control device 13 determines whether or not the wafer 30 has been placed on the rotating device 11 (S101). This determination is made, for example, based on whether or not the control device 13 has completed the task of placing the wafer 30 by controlling the robot. If a separate control device controls the robot, the control device 13 may receive notification from the robot's control device that the task of placing the wafer 30 on the rotating device 11 has been completed.

[0034] Next, the control device 13 controls the motor 12 to rotate the rotating device 11, thereby rotating the wafer 30 once (S102). Furthermore, the control device 13 uses the sensor 14 to detect defects and notches 33 on the edge of the wafer 30 (S102). By measuring the edge of the wafer 30 with the sensor 14 while rotating the wafer 30 once, defects on the wafer 30 can be inspected all around. In addition, since the sensor 14 in this embodiment simultaneously detects edge defects and notches 33, the time required for wafer inspection and alignment can be shortened.

[0035] If a notch 33 is detected, the control device 13 records the position of the notch 33 based on the encoder's detection value at the time the notch 33 was detected (S103). The position of the notch 33 is recorded as the rotational phase of the wafer 30 (rotating device 11) at the time the notch 33 was detected.

[0036] Next, the control device 13 transmits the defect detection result of the wafer 30 performed in step S102 to the external device 40 via the communication device 16 (S104). The defect detection result of the wafer 30 is transmitted in association with the identification information of the wafer 30. The external device 40 determines whether the defect detection result of the wafer 30 is at a level that is acceptable for a product. If the external device 40 determines that there is no problem, the aligner device 1 (control device 13) may continue the alignment, or the external device 40 may make a determination regarding the defects of the wafer 30 after the aligner device 1 (control device 13) has completed the alignment of one or more wafers 30.

[0037] Next, the control device 13 adjusts the rotational phase of the wafer 30 to match the rotational phase of the wafer 30 to a predetermined value (S105). That is, the control device 13 controls the motor 12 to rotate the wafer 30 so that the position of the notch recorded in step S103 faces a predetermined direction.

[0038] As a result, alignment and wafer inspection can be performed using the same device. This reduces the processing time for wafer 30 compared to when alignment and wafer inspection are performed using separate devices. In particular, the sensor 14 is configured to detect defects in wafer 30 by irradiating it with multiple beams of light traveling in different directions, thus enabling accurate detection of various defects in wafer 30.

[0039] Next, a second embodiment will be described with reference to Figure 4.

[0040] In the first embodiment, the sensor for detecting defects in the wafer 30 and the sensor for detecting notches 33 in the wafer 30 are the same. Instead, in the second embodiment, the sensor for detecting defects in the wafer 30 and the sensor for detecting notches 33 in the wafer 30 are different. Specifically, a sensor 14 equivalent to that in the first embodiment is used to detect defects in the wafer 30, and a line sensor 15 is used to detect notches 33 in the wafer 30.

[0041] The line sensor 15 is a transmissive light intensity measuring sensor. The line sensor 15 comprises a light-emitting unit 15a and a light-receiving unit 15b.

[0042] The light-emitting unit 15a emits light toward the light-receiving unit 15b. The light emitted by the light-emitting unit 15a has a linear cross-section. A wafer 30 is placed between the light-emitting unit 15a and the light-receiving unit 15b.

[0043] The light receiving unit 15b receives the light emitted by the light emitting unit 15a that is not blocked by the wafer 30. The light receiving unit 15b generates a current signal (or a voltage signal converted therefrom) corresponding to the amount of light received and outputs it to the control device 13. When a notch 33 exists between the light emitting unit 15a and the light receiving unit 15b, less light is blocked by the wafer 30, so the value of the current signal output by the light receiving unit 15b increases. Therefore, the position (rotational phase) of the notch 33 can be determined based on the output value of the light receiving unit 15b. If the center position of the wafer 30 is shifted, the value of the current signal output by the light receiving unit 15b will constantly change as the wafer 30 rotates, so the control device 13 can detect that the center position of the wafer 30 is shifted.

[0044] In the second embodiment, the two functions performed by sensor 14 are distributed to two sensors. This allows the function or settings of sensor 14 to be specialized for detecting defects in wafer 30. As a result, it may be possible to further improve the accuracy of defect detection in wafer 30. The control related to defect detection and alignment of wafer 30 is the same as in the first embodiment.

[0045] As described above, the aligner device 1 of this embodiment comprises a motor 12, a rotating device 11, a control device 13, and a sensor 14. The motor 12 generates rotational driving force. The rotating device 11 rotates while supporting the wafer 30 by the rotational driving force generated by the motor 12. The control device 13 controls the rotation of the rotating device 11 to adjust the rotational phase of the wafer 30 to a predetermined value. The sensor 14 detects defects on the edge of the wafer 30 by irradiating the edge of the wafer 30 with multiple beams of light traveling in different directions and receiving the light.

[0046] By detecting defects on the edges of the wafer 30 using this method, inspection can be performed at multiple locations on the wafer 30, enabling high-precision detection of defects in the wafer 30. Furthermore, since the aligner device 1 detects defects in the wafer 30 as well as alignment, the time required for wafer inspection and alignment can be reduced.

[0047] In the aligner apparatus 1 of this embodiment, the control device 13 rotates the wafer 30 at least once before adjusting the rotational phase of the wafer 30 to a predetermined value. The sensor 14 continues to detect defects on the edges of the wafer 30 while the control device 13 rotates the wafer 30 once.

[0048] This allows for efficient inspection and alignment of the wafer 30. Furthermore, it enables inspection of the wafer 30 around its entire circumference.

[0049] In the aligner apparatus 1 of this embodiment, the control device 13 adjusts the rotational phase of the wafer 30 to a predetermined value based on an orientation flat or notch 33 formed on the wafer 30. The orientation flat or notch 33 is detected using a sensor 14.

[0050] This allows for a reduction in the number of sensors, thereby lowering the cost of the aligner device.

[0051] The aligner device 1 of this embodiment includes a communication device 16 that communicates with an external device 40. The communication device 16 transmits the detection results of defects on the edges of the wafer 30 to the external device 40, associating them with the identification information of the wafer 30.

[0052] This allows the external device 40 to determine whether the defect detection results for the wafer 30 are at a level that is acceptable for a product.

[0053] In the aligner apparatus 1 of this embodiment, the sensor 14 detects defects on the side surface 32 of the wafer 30 without detecting defects on the main surface 31 of the wafer 30. The control device 13 determines the defects on the main surface 31 of the wafer 30 based on the defects on the side surface 32 of the wafer 30.

[0054] This allows for a shorter inspection time compared to a configuration that inspects the entire main surface 31 of the wafer 30. Furthermore, if more than a predetermined value of fine particles accumulates on the main surface 31 of the wafer 30, there is a high probability that more than a predetermined value of fine particles will also accumulate on the edges of the wafer 30, thus ensuring sufficient inspection accuracy.

[0055] Although preferred embodiments of this application have been described above, the above configuration can be modified as follows, for example.

[0056] In the above embodiment, the light-emitting unit 22 emits light, and the light-receiving unit 23 receives the light that is reflected from the surface of the wafer 30. Alternatively, the light-emitting unit 22 emits light, and the light-receiving unit 23 may receive the light that is reflected from the surface of the wafer 30.

[0057] In the above embodiment, the light-emitting unit 22 and the light-receiving unit 23 are arranged in the first part 21a, and the light-emitting unit 22 and the light-receiving unit 23 are arranged in the second part 21b. Alternatively, the light-emitting unit 22 may be arranged in the first part 21a and the light-receiving unit 23 may be arranged in the second part 21b (or vice versa).

[0058] The flowchart shown in the above embodiment is just an example, and some processes may be omitted, some processes may be modified, or new processes may be added. For example, in the above embodiment, the processes for detecting defects and notches 33 on the wafer 30 are performed simultaneously. Alternatively, the process for detecting defects on the wafer 30 may be performed first, followed by the process for detecting notches 33 on the wafer 30. Also, the order of the processes in step S104 and step S105 may be reversed.

[0059] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, dedicated processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions, or hardware programmed to perform the enumerated functions. The hardware may be hardware disclosed herein, or other known hardware that is programmed or configured to perform the enumerated functions. If the hardware is a processor, which is considered a type of circuit, then the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or the processor.

Claims

1. A motor that generates rotational driving force, A rotating device that rotates while supporting a wafer by the rotational driving force generated by the motor, A control device that controls the rotation of the rotating device and performs a process to adjust the rotational phase of the wafer to a predetermined value, A sensor that detects defects on the side surface of a wafer by individually irradiating multiple directional beams of light with different directions of propagation toward the side surface of the wafer edge, and individually receiving multiple beams of light that are affected by the surface of the wafer's side surface, An aligner device equipped with the following features.

2. The aligner device according to claim 1, The control device rotates the wafer at least once before adjusting the rotational phase of the wafer to a predetermined value. The sensor is an aligner device that continuously detects defects on the side surface of the wafer while the control device rotates the wafer once.

3. The aligner device according to claim 2, The control device adjusts the rotational phase of the wafer to a predetermined value based on the orientation flat or notch formed on the wafer. The orientation flat or the notch is detected using the sensor in the aligner device.

4. The aligner device according to claim 1, Equipped with a communication device for communicating with external devices, The communication device is an aligner device that transmits the detection results of defects on the side surface of the wafer, associated with the identification information of the wafer, to the external device.

5. An aligner device according to any one of claims 1 to 4, The sensor detects defects on the side surface of the wafer without detecting defects on the main surface of the wafer. The control device is an aligner device that determines defects on the main surface of the wafer based on defects on the side surface of the wafer.