Wafer lateral laser alignment device

Abstract

This utility model relates to the field of semiconductor processing technology, and in particular to a wafer lateral laser alignment device, comprising: a substrate and a stage assembly mounted on the substrate; a lateral moving assembly is disposed above the substrate, and a laser emitting unit and a photoelectric detection unit are respectively mounted on the upper two sides of the lateral moving assembly; wherein, a parallel beam is formed between the laser emitting unit and the photoelectric detection unit, and the parallel beam is parallel to the reference edge of the wafer. This utility model proposes an innovative wafer positioning method, abandoning the traditional vertical illumination scheme of the upper surface, and adopting a method in which the parallel beam is parallel to the reference edge of the wafer, directly illuminating its radial cross-section. When the laser sweeps across, the solid part of the wafer will completely block the parallel beam, while at the reference edge, the laser is allowed to pass through because there is no solid blockage. The strong signal contrast generated between "blocked" and "unblocked" forms a clear and unique identification feature.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor processing technology, and in particular to a wafer lateral laser alignment device. Background Technology

[0002] In the semiconductor manufacturing field, wafer alignment is the core process of photolithography. By identifying the notch or flat edge of the wafer, it achieves precise positioning of the wafer and the photolithography equipment, which directly determines the manufacturing accuracy and yield of the chip.

[0003] As shown in the attached diagram of the instruction manual. Figure 1 As shown, the industry currently widely adopts the "vertical laser illumination" method: the laser is emitted vertically from directly above the wafer, penetrates the wafer, and is captured by a detector below. The reference position is determined by analyzing the signal difference between the "shielded area" and the "unshielded area". This method is stable and reliable for traditional opaque silicon wafers.

[0004] However, with the widespread adoption of third-generation semiconductor materials such as silicon carbide and gallium nitride, the limitations of this approach have become increasingly apparent. These new wafer materials are semi-transparent or transparent, causing most of the laser light to penetrate directly, producing only weak signal changes at the notch / flat edge. This results in extremely small signal differences between the "shielded area" and the "unshielded area," leading to a very low signal-to-noise ratio and making it highly susceptible to identification errors. Statistics show that for semi-transparent wafers, the alignment failure rate of traditional methods can reach 15%-25%, severely impacting process stability and production efficiency, becoming a key technological bottleneck restricting the manufacturing of new semiconductors.

[0005] Therefore, it is urgent to develop a high-precision alignment technology suitable for new wafers. Utility Model Content

[0006] The purpose of this invention is to address the shortcomings of existing technologies, such as the high failure rate of traditional alignment methods for third-generation semiconductor materials like silicon carbide and gallium nitride, and to propose a wafer lateral laser alignment device.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: Design a wafer lateral laser alignment device, including: A substrate and a stage assembly mounted on the substrate; A transverse moving assembly is disposed above the substrate, and a laser emitting unit and a photoelectric detection unit are respectively mounted on the upper two sides of the transverse moving assembly; A parallel beam is formed between the laser emitting unit and the photoelectric detection unit. The parallel beam is parallel to the reference edge of the wafer side, and the height of the parallel beam is adapted to the thickness of the wafer.

[0008] Furthermore, the lateral movement assembly includes a slide block slidably connected to the substrate; Two upright plates are fixedly installed above the slide block, and the laser emitting unit and the photoelectric detection unit are respectively installed on opposite sides of the two upright plates.

[0009] Furthermore, the slide block is slidably connected to the base plate via a sliding structure, and the sliding direction of the slide block is perpendicular to the rotation axis of the stage assembly. A drive assembly for driving the slide block to move laterally is also installed above the base plate.

[0010] Furthermore, a cable chain is also installed between the slide and the base plate; A cable management cover located between two upright plates is fixedly installed above the slide block.

[0011] Furthermore, the stage assembly includes: A motor bracket fixedly installed below the substrate; A rotary motor is fixedly installed below the motor bracket. The shaft end of the rotary motor is connected to a rotating rod, and the upper end of the rotating rod passes through the base plate and is connected to a platform.

[0012] Furthermore, the shaft end of the rotary motor is fixedly connected to the rotating rod via a coupling, and a rotary joint is also installed on the outside of the rotating rod.

[0013] Furthermore, the rotating rod has an air passage formed inside, extending to its upper end. The fixed part of the rotary joint is connected to the air passage through an air pipe and a connector. The rotating part of the rotary joint is connected to a negative pressure device through an air pipe and a connector.

[0014] Furthermore, an adsorption groove is formed on the upper part of the stage; A cavity is provided inside the stage, and air holes are connected between the cavity and the adsorption tank.

[0015] Furthermore, a sleeve is fixedly installed below the platform, and the sleeve is sleeved on the outside of the rotating rod and circumferentially locked. The sleeve portion is threadedly connected to a locking element on its outer side, and the rotating rod has an inwardly recessed groove on its outer side that is adapted to the locking element.

[0016] Furthermore, an insertion hole communicating with the cavity is provided below the platform, the upper end of the rotating rod is inserted into the insertion hole, and a sealing gasket is installed between the insertion hole and the rotating rod.

[0017] The wafer lateral laser alignment device proposed in this invention has the following advantages: This invention proposes an innovative wafer positioning method that abandons the traditional method of vertically irradiating the upper surface. Instead, it uses a parallel beam of light parallel to the reference edge of the wafer to directly irradiate its radial cross-section. When the laser sweeps across, the solid part of the wafer completely blocks the parallel beam of light, while at the reference edge, the laser is allowed to pass through due to the absence of physical obstruction. The strong signal contrast generated between "obstruction" and "unobstruction" constitutes a clear and unique identification feature. This method cleverly transforms the differences in physical structure into optical signals that can be accurately captured, thereby achieving rapid and high-precision positioning of wafer notches or flat edges, effectively improving the accuracy and reliability of detection. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a wafer alignment scheme in the prior art; Figure 2 This is a perspective view of the present utility model; Figure 3 This is a top view of the present invention; Figure 4 This is a side view of the present invention; Figure 5 This is a cross-sectional view of the present invention. Figure 6 for Figure 5 A magnified structural diagram of area A; Figure 7 This is a schematic diagram of the signal curve of the lateral alignment scheme of this utility model.

[0019] In the diagram: 1. Substrate; 2. Stage assembly; 21. Motor bracket; 22. Rotary motor; 23. Rotating rod; 231. Air passage; 232. Inward-curving slant; 24. Stage; 241. Adsorption tank; 242. Cavity; 243. Air hole; 244. Insertion hole; 25. Coupling; 26. Rotary joint; 27. Sleeve section; 28. Locking element; 29. ​​Sealing gasket; 3. Lateral movement assembly; 31. Slide; 32. Vertical plate; 33. Sliding structure; 34. Drive assembly; 35. Cable drag chain; 36. Cable cover; 4. Laser emitting unit; 40. Parallel beam; 5. Photoelectric detection unit; 6. Wafer. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0021] Reference Figure 2-7As an embodiment of the utility model, a wafer lateral laser alignment device is disclosed. Specifically, the laser alignment device includes a substrate 1 and a stage assembly 2 mounted on the substrate 1. In this embodiment, the stage assembly 2 is used to support a wafer 6. Of course, the wafer 6 can be transferred and positioned above the stage assembly 2 by a robotic arm. A transverse moving assembly 3 is disposed above the substrate 1, and a laser emitting unit 4 and a photoelectric detection unit 5 are respectively installed on the upper two sides of the transverse moving assembly 3; A parallel beam 40 is formed between the laser emitting unit 4 and the photoelectric detection unit 5. The parallel beam 40 is parallel to the reference edge of the wafer 6, and the height of the parallel beam 40 is adapted to the thickness of the wafer 6.

[0022] Specifically, in this invention, the reference edge of the wafer 6 is a notch formed on the outer periphery of the wafer 6. The principle that the parallel beam 40 can pass through the flat edge is used to achieve the positioning of the wafer 6. In addition, in this embodiment, the height of the parallel beam 40 is not greater than the thickness of the wafer 6, so as to avoid the parallel beam 40 not being completely blocked, which would cause detection error.

[0023] Of course, the laser emitting unit 4 and the photoelectric detection unit 5 described in this invention can directly adopt the laser emitter and photoelectric detector in the prior art. Their specific structure and principle are conventional technical means for those skilled in the art, and their principles will not be elaborated here.

[0024] This invention proposes an innovative wafer positioning method that abandons the traditional method of vertically irradiating the upper surface. Instead, it uses a parallel beam 40 parallel to the reference edge of wafer 6, directly irradiating its radial cross-section. When the laser sweeps across, the solid part of wafer 6 completely blocks the parallel beam 40, while the reference edge is unblocked, allowing the laser to pass through. The strong signal contrast between "blocked" and "unblocked" forms a clear and unique identification feature. This method cleverly transforms physical structural differences into optical signals that can be accurately captured, thereby achieving rapid and high-precision positioning of notches or flat edges of wafer 6, effectively improving the accuracy and reliability of detection.

[0025] In some embodiments, the transverse component 3 of the present invention includes a slide block 31 slidably connected to the substrate 1; Two upright plates 32 are fixedly installed above the slide block 31. The laser emitting unit 4 and the photoelectric detection unit 5 are respectively installed on opposite sides of the two upright plates 32. Of course, in this embodiment, the two upright plates 32 are vertically connected above the slide block 31, and the two upright plates 32 are horizontally arranged so that the laser emitting unit 4 and the photoelectric detection unit 5 can form a parallel beam 40 parallel to the reference edge.

[0026] Furthermore, in this embodiment, the slide block 31 is slidably connected to the base plate 1 via a sliding structure 33. Optionally, the sliding structure 33 in this embodiment can be configured as a guide rail and a slider. The guide rod is fixedly installed on the base plate 1, and the slider and the slide block 31 are fixedly connected and slidably connected to the guide rail, thereby achieving stable support and sliding of the slide block 31. The sliding direction of the slide block 31 is perpendicular to the rotation axis of the platform assembly 2. A drive assembly 34 for driving the slide block 31 to move laterally is also installed above the base plate 1. In this embodiment, the drive assembly 34 is configured as a motor and a lead screw. The shaft end of the motor is fixedly connected to the lead screw, and the lead screw and the slide block 31 are connected through a nut seat, thereby achieving the movement drive of the slide block 31. This method is a conventional technical means for those skilled in the art and will not be described in detail here.

[0027] In this embodiment, by designing the slide 31 to be movable, the initial position of the wafer 6 with different diameters can be easily adjusted to optimize its applicability.

[0028] Based on the above embodiments, in this embodiment, a drag chain 35 is also installed between the slide block 31 and the substrate 1. The drag chain 35 is used to facilitate the routing of the laser emitting unit 4 and the photoelectric detection unit 5 to meet the movable requirements of the slide block 31. A cable routing cover 36 is fixedly installed above the slide block 31 between the two upright plates 32. Specifically, in this embodiment, the cable routing cover 36 can be fixed above the slide block 31 by bolts. Its middle part has a U-shaped structure to form a channel for cable routing. Through the design of the cable routing cover 36, components away from the drag chain 35 can be conveniently routed and protected, thereby further improving the applicability of this device.

[0029] In some embodiments, the platform assembly 2 of this invention includes: A motor bracket 21 is fixedly installed below the base plate 1; A rotary motor 22 is fixedly installed below the motor bracket 21. The shaft end of the rotary motor 22 is connected to a rotating rod 23. The upper end of the rotating rod 23 passes through the substrate 1 and is connected to a stage 24. Of course, the wafer 6 is placed on top of the stage 24.

[0030] Specifically, in this embodiment, the shaft end of the rotary motor 22 is fixedly connected to the rotating rod 23 via a coupling 25. A rotary joint 26 is also installed on the outside of the rotating rod 23. Of course, the rotary motor 22 in this embodiment can be a high-precision servo motor or a piezoelectric ceramic motor, so as to facilitate precise control of the rotation angle of the platform 24.

[0031] Based on the above embodiments, in this embodiment, the rotating rod 23 has an air passage 231 formed inside, extending to its upper end. The fixed part of the rotary joint 26 is connected to the air passage 231 through an air pipe and a connector. The rotating part of the rotary joint 26 is connected to a negative pressure device through an air pipe and a connector.

[0032] Of course, the specific structure of the rotary joint 26 described in this embodiment is existing technology. The fixed part and the rotating part are the inner and outer parts of the main body of the rotary joint 26. The two parts are rotatably connected and sealed. The specific principle can be referred to the existing technology, and will not be elaborated here.

[0033] Specifically, in this embodiment, a rotary joint 26 is used to open the negative pressure air passage. Since the rotating rod 23 is connected by rotation, the rotary joint 26 can be used to generate a stable negative pressure inside the air passage 231.

[0034] Of course, in order to achieve adsorption and fixation of wafer 6, an adsorption groove 241 is formed on the upper part of the stage 24 described in this utility model; A cavity 242 is also provided inside the stage 24, and an air hole 243 is connected between the cavity 242 and the adsorption tank 241.

[0035] Specifically, in this embodiment of the present invention, a sleeve portion 27 is fixedly installed below the platform 24. The sleeve portion 27 is sleeved on the outside of the rotating rod 23 and circumferentially locked. The circumferential locking method can be a combination of a groove and a slider. That is, a groove is opened on the outside of the rotating rod 23, and a slider is formed inside the sleeve portion 27. The slider and the groove slide together to prevent circumferential rotation between the rotating rod 23 and the platform 24. The sleeve portion 27 is threadedly connected to a locking member 28 on its outer side, and the rotating rod 23 has an inwardly recessed groove 232 on its outer side that is adapted to the locking member 28.

[0036] It should be noted that the locking member 28 described in this embodiment is a bolt. There can be two locking members 28. When connecting the rotating rod 23 and the platform 24, firstly, the sleeve part 27 is sleeved on the upper end of the rotating rod 23, and then the locking member 28 is rotated. Since the end of the locking member 28 will abut against the outer wall of the inward inclined groove 232, with the help of the inclined surface of the inward inclined groove 232, the entire sleeve part 27 will move downward a small distance during the process of pressing the locking member 28 in, so as to achieve stable installation of the platform 24.

[0037] Based on the above embodiments, in this embodiment, the stage 24 is provided with an insertion hole 244 communicating with the cavity 242. The insertion hole 244 is a stepped hole. The upper end of the rotating rod 23 is inserted into the insertion hole 244. A sealing gasket 29 is installed between the insertion hole 244 and the rotating rod 23. That is, in this embodiment, a negative pressure air path is formed by the air passage 231, the insertion hole 244, the cavity 242, the air hole 243 and the adsorption groove 241, so as to stably adsorb the wafer 6. In addition, the sealing gasket 29 used in this embodiment can improve the connection sealing between the rotating rod 23 and the stage 24.

[0038] The specific alignment process includes the following steps: Step S1: Positioning of Wafer 6 and Laser Beam Calibration Place the wafer 6 to be aligned on the stage 24 so that the wafer 6 is in a horizontal state, start the laser emitting unit 4, and ensure that the emitted laser parallel beam 40 is completely parallel to the surface of the wafer 6, and that the propagation path of the parallel beam 40 is perpendicular to the radial direction of the wafer 6. At the same time, ensure that the parallel beam 40 just illuminates the edge cross section of the wafer 6, not the upper or lower surface. Step S2: Parallel beam 40° scan and signal capture The laser emitting unit 4 emits a continuous and stable laser beam. The height of the parallel beam 40 matches the thickness of the wafer 6 to ensure complete coverage of the cross-section of the wafer 6. At the same time, the wafer 6 stage 24 drives the wafer 6 to rotate slowly around the center axis. At the end of the propagation path of the parallel beam 40, the photoelectric detection unit 5 is activated to capture the laser signal in real time. like Figure 7 As shown, when the photodetector 5 illuminates the solid edge cross-section of the wafer 6, the laser beam is completely blocked by the solid wafer 6, and the signal strength received by the photodetector 5 is extremely low (close to zero). When the wafer rotates to the notch edge position, the laser beam is no longer blocked by the wafer 6 and will directly penetrate the notch edge area. The signal strength received by the photodetector 5 instantly reaches its peak value. Through the signal change during the rotation of the wafer 6, a clear pulse curve of low signal-peak signal-low signal can be formed.

[0039] 3. Step S3: Signal Analysis and Reference Position Determination The signal captured by the photoelectric detection unit 5 is transmitted to the signal processing module. The signal filtering algorithm removes interference noise such as ambient light and extracts clear signal pulse features. Based on the time point of the pulse signal and the rotation speed of the wafer 6, the specific angular position of the notch flat edge on the circumference of the wafer 6 is calculated, which is used as the alignment reference for the wafer. 4. Step S4: Wafer 6-position adjustment and precise alignment The reference position information is transmitted to the control module. The control module, in conjunction with the preset alignment target position, calculates the current offset (X / Y direction) and rotation deviation angle of wafer 6. It then drives the wafer stage 24 to rotate and adjust wafer 6 until the notch edge of wafer 6 is completely aligned with the reference mark of the photolithography equipment, thus completing the alignment.

[0040] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A wafer lateral laser alignment device, characterized in that, include: The substrate (1) and the stage assembly (2) mounted on the substrate (1). A transverse component (3) is provided above the substrate (1), and a laser emitting unit (4) and a photoelectric detection unit (5) are respectively installed on the upper two sides of the transverse component (3). A parallel beam (40) is formed between the laser emitting unit (4) and the photoelectric detection unit (5). The parallel beam (40) is parallel to the reference edge of the wafer (6), and the height of the parallel beam (40) is adapted to the thickness of the wafer (6).

2. The wafer lateral laser alignment device according to claim 1, characterized in that: The transverse component (3) includes a slide (31) slidably connected to the substrate (1). Two upright plates (32) are fixedly installed above the slide (31), and the laser emitting unit (4) and the photoelectric detection unit (5) are respectively installed on opposite sides of the two upright plates (32).

3. The wafer lateral laser alignment device according to claim 2, characterized in that: The slide (31) is slidably connected to the base plate (1) via a sliding structure (33). The sliding direction of the slide (31) is perpendicular to the rotation axis of the stage assembly (2). A drive assembly (34) for driving the slide (31) to move laterally is also installed above the base plate (1).

4. The wafer lateral laser alignment device according to claim 2, characterized in that: A cable chain (35) is also installed between the slide (31) and the base plate (1). A cable tray (36) is fixedly installed above the slide (31) between the two upright plates (32).

5. The wafer lateral laser alignment device according to claim 1, characterized in that: The platform assembly (2) includes: A motor bracket (21) is fixedly installed below the base plate (1). A rotary motor (22) is fixedly installed below the motor bracket (21). The shaft end of the rotary motor (22) is connected to a rotating rod (23). The upper end of the rotating rod (23) passes through the base plate (1) and is connected to a platform (24).

6. A wafer lateral laser alignment device according to claim 5, characterized in that: The shaft end of the rotary motor (22) is fixedly connected to the rotating rod (23) via a coupling (25), and a rotary joint (26) is also installed on the outside of the rotating rod (23).

7. A wafer lateral laser alignment device according to claim 6, characterized in that: The rotating rod (23) has an air passage (231) formed inside, extending to its upper end. The fixed part of the rotary joint (26) is connected to the air passage (231) through an air pipe and a connector. The rotating part of the rotary joint (26) is connected to a negative pressure device through an air pipe and a connector.

8. A wafer lateral laser alignment device according to claim 6, characterized in that: An adsorption groove (241) is formed on the top of the stage (24). A cavity (242) is also provided inside the stage (24), and an air hole (243) is connected between the cavity (242) and the adsorption tank (241).

9. A wafer lateral laser alignment device according to claim 8, characterized in that: A sleeve (27) is fixedly installed below the platform (24). The sleeve (27) is sleeved on the outside of the rotating rod (23) and circumferentially locked. The sleeve portion (27) is threadedly connected to a locking member (28), and the outer side of the rotating rod (23) has an inwardly recessed groove (232) adapted to the locking member (28).

10. A wafer lateral laser alignment device according to claim 9, characterized in that: The platform (24) has an insertion hole (244) that communicates with the cavity (242) below it. The upper end of the rotating rod (23) is inserted into the insertion hole (244). A sealing gasket (29) is installed between the insertion hole (244) and the rotating rod (23).

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