Wafer carrier

Abstract

The application discloses a wafer carrier, and belongs to the technical field of semiconductor wafer detection equipment. The wafer carrier comprises a fixing module, a switching module and a rotating module. The wafer carrier has a first working mode and a second working mode. In the first working mode, the second suction disc assembly is lifted to a position higher than the first suction disc assembly to adsorb a first-size wafer. In the second working mode, the second suction disc assembly is lowered to a position lower than the first suction disc assembly, and a ring-shaped bearing surface formed by the first suction disc assembly adsorbs a second-size wafer. After the two-size wafers are adsorbed, the upper surfaces are in the same horizontal plane, so that the working distance of an optical detection lens remains constant and needs not to be recalibrated. The application realizes automatic compatibility of a single carrier for two-size wafers, eliminates the process of manually replacing the carrier, and improves the automation level and detection precision consistency of semiconductor detection.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor wafer inspection equipment technology, specifically relating to a wafer stage, which is mainly used in the automatic optical inspection process of third-generation semiconductor substrates such as silicon carbide and epitaxial wafers, to achieve automatic compatible adsorption, fixation and rotation positioning of two wafers of different sizes. Background Technology

[0002] With the rapid development of new energy, 5G communications, and other fields, the demand for third-generation semiconductor materials, represented by silicon carbide, continues to grow. Silicon carbide wafer manufacturing is at a critical technological juncture, transitioning from 6-inch to 8-inch wafers, and many production lines simultaneously require the inspection of both 6-inch and 8-inch wafers. As the core component of inspection equipment that supports and fixes the wafers, the performance of the wafer stage directly affects inspection accuracy and production efficiency; therefore, there is an urgent need for multi-size compatibility of the stage.

[0003] In existing technologies, wafer stages used for silicon carbide wafer inspection are typically designed with a single size, meaning one device can only accommodate one type of wafer. When the production line needs to switch from one wafer size to another, operators must manually replace the entire stage or adjust complex mechanical mechanisms. This process is time-consuming, significantly reduces inspection efficiency, and frequent manual operations increase the risk of particulate contamination in the cleanroom environment, posing a potential threat to product yield.

[0004] Furthermore, manually changing the stage inevitably alters the working distance of the optical inspection system, requiring re-focusing and recalibration. This repetitive calibration process not only increases equipment downtime but may also affect the consistency and repeatability of batch-to-batch inspection results due to the accumulation of calibration errors. Therefore, there is an urgent need to develop a wafer stage that can automatically accommodate wafers of various sizes, reduce manual intervention, and maintain a constant working distance for the inspection optical engine. Summary of the Invention

[0005] The purpose of this invention is to provide a wafer stage that solves the problems of existing wafer stages being designed with a single size. When switching between wafers of different sizes on the production line, operators need to manually change the stage or make complex adjustments, which leads to reduced detection efficiency, increased risk of cleanroom contamination, and affects the consistency of detection accuracy and equipment stability due to the recalibration of the working distance of the optical detection system.

[0006] To address the above problems, the present invention provides a wafer stage, comprising a fixing module, a switching module, and a rotating module; The fixing module includes a fixing base plate, a support column, and a first suction cup assembly; the fixing base plate is connected to the rotating module, the support column is fixed on the fixing base plate, and the first suction cup assembly is fixed above the fixing base plate through the support column. The first suction cup assembly has a ring structure and forms an accommodating space inside. The switching module includes a lifting mechanism and a second suction cup assembly. The second suction cup assembly is a disc-shaped structure, located within the accommodating space of the first suction cup assembly, and its outer diameter is smaller than the inner diameter of the first suction cup assembly. The second suction cup assembly and the first suction cup assembly are coaxially arranged and do not contact each other. The lifting mechanism is located on a fixed base plate and connected to the bottom of the second suction cup assembly. The lifting mechanism can drive the second suction cup assembly to move in the vertical direction. The wafer stage has a first operating mode and a second operating mode; In the first working mode, the lifting mechanism drives the second suction cup assembly to rise to the first position. The upper surface of the second suction cup assembly is higher than the upper surface of the first suction cup assembly, which is used to support and adsorb and fix the first size wafer. In the second working mode, the lifting mechanism drives the second suction cup assembly to descend to the second position. The upper surface of the second suction cup assembly is lower than the upper surface of the first suction cup assembly. The upper surface of the first suction cup assembly forms an annular bearing surface for bearing and adsorbing and fixing the second-sized wafer. When the first-sized wafer is adsorbed onto the second suction cup assembly, the first horizontal plane on which its upper surface is located is the same horizontal plane as the second-sized wafer on which its upper surface is located when it is adsorbed onto the first suction cup assembly.

[0007] Furthermore, a repeating positioning structure is provided between the bottom surface of the first suction cup assembly and the top surface of the support column, and between the bottom surface of the second suction cup assembly and the second suction cup seat. The repeating positioning structure includes a positioning pin and a positioning bushing.

[0008] Furthermore, the first suction cup assembly and the support column, as well as the second suction cup assembly and the second suction cup base, are connected by a magnetic quick-lock mechanism or a snap-lock mechanism.

[0009] Furthermore, the support column is made of Invar or microcrystalline glass, and has through holes extending along its axial direction inside, which are filled with phase change material; a flexible heat insulation pad is provided between the bottom of the support column and the fixed base plate.

[0010] Furthermore, the outer periphery of the second suction cup assembly and the inner periphery of the first suction cup assembly are both provided with rounded chamfers, and the surfaces of the rounded chamfers are polished.

[0011] Furthermore, the guide assembly adopts a cross roller slide rail structure, and a preload spring is provided between the slider and the slide rail to eliminate backlash during the movement.

[0012] Furthermore, the connection between the rotating disk and the fixed base plate is provided with an annular guide groove and a ball bearing assembly; the annular guide groove is coaxially opened on the upper surface of the rotating disk, and the ball bearing assembly is embedded in the annular guide groove and fits against the lower surface of the fixed base plate; a torque sensor and a deceleration buffer mechanism are provided on the output shaft of the rotary motor, the torque sensor is used to monitor the output torque of the rotary motor in real time, and the deceleration buffer mechanism is used to reduce the impact when the rotating module starts and stops.

[0013] Furthermore, the support column is a telescopic structure, including a fixed section and a telescopic section; the fixed section is fixedly connected to the fixed base plate, and the telescopic section is fixedly connected to the first suction cup assembly; the telescopic section is equipped with locking bolts to fix the height of the telescopic section; the support column is equipped with height scale lines to assist in adjusting the height of the support column.

[0014] The present invention has the following beneficial effects: (1) This invention achieves automatic compatibility switching between two different wafer sizes using a single stage by setting up a coaxially nested first suction cup assembly and a second suction cup assembly, and by using a lifting mechanism to drive the second suction cup assembly to move in the vertical direction. When switching wafer sizes, there is no need for operators to manually replace stage components or make complex mechanical adjustments. The entire switching process is automatically completed by the control system, eliminating the risk of cleanroom contamination caused by manual intervention and improving the automation level and production efficiency of the semiconductor testing process.

[0015] (2) By setting the height positions of the first and second suction cup components in different working modes, this invention ensures that the upper surface of the wafer remains at the same horizontal plane regardless of the size of the wafer being suctioned. As a result, the working distance of the optical inspection lens remains constant before and after wafer size switching, eliminating the need for recalibration and re-calibration of the height, thus ensuring the consistency and repeatability of the inspection accuracy and providing a stable and reliable basic platform for the precision inspection of silicon carbide substrates and epitaxial layers.

[0016] (3) The independent vacuum pipeline of this invention ensures that the adsorption gas path does not interfere with each other in the two working modes. The limiting component and the buffer component respectively ensure the lifting positioning accuracy and the smoothness of movement. The measuring component realizes the closed-loop control of the lifting displacement. The annular groove or adsorption hole array on the surface of the suction cup makes the vacuum adsorption force evenly distributed. The rotating module drives the wafer to rotate smoothly. The overall structure is compact and reliable in operation, taking into account multi-size compatibility, convenient operation and long-term operation stability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art 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.

[0018] Figure 1 This is a structural diagram of the wafer stage in an embodiment of the present invention; Figure 2 This is a structural diagram of the lifting structure of the wafer stage in an embodiment of the present invention; Figure 3 This is a structural diagram of the wafer stage switching module in an embodiment of the present invention; Figure 4 This is a diagram of the robotic arm-free structure of the wafer stage in an embodiment of the present invention; Figure 5 This is a top view of the wafer stage in an embodiment of the present invention; Figure 6 This is a cross-sectional view of the wafer carrier in an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached drawings: 1-Rotation module; 1.1-Rotation base; 1.2-Rotation disk; 2-Switching module; 2.1-Second suction cup seat; 2.2-Limiting component; 2.4-Buffer component; 2.5-Measuring component; 2.6-Power component; 2.7-Lifting base; 2.8-Second suction cup assembly; 2.9-Slider; 2.10-Slide rail; 2.11-Connecting device; 3-Fixing module; 3.1-Fixing base plate; 3.2-Support column; 3.3-First suction cup assembly; 4-Robot arm. Detailed Implementation

[0020] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0021] To fully understand this invention, detailed steps and structures will be presented in the following description to illustrate the technical solution of this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0022] like Figures 1 to 6 In one embodiment of the wafer stage of the present invention, the wafer stage includes a fixing module 3, a switching module 2, and a rotating module 1. The wafer stage can automatically accommodate two different wafer sizes and maintain a constant height of the upper surface of the wafer when switching wafer sizes, without the need for manual replacement of components or recalibration of the working distance of the optical inspection system.

[0023] The fixing module 3 includes a fixing base plate 3.1, support columns 3.2, and a first suction cup assembly 3.3. The fixing base plate 3.1 is a rigid flat plate structure. The lower surface of the fixing base plate 3.1 is fixedly connected to the rotating disk 1.2 of the rotating module 1 by bolts and rotates synchronously with the rotating disk 1.2. The support column 3.2 is a columnar structure extending vertically. The bottom end of the support column 3.2 is fixed to the upper surface of the fixing base plate 3.1 by screws. The number of support columns 3.2 can be set according to the size of the platform and the load-bearing requirements, for example, three or four evenly distributed along the circumference. The first suction cup assembly 3.3 is supported and fixed above the fixing base plate 3.1 by the support columns 3.2. An installation space for accommodating the switching module 2 is formed between the first suction cup assembly 3.3 and the fixing base plate 3.1. The first suction cup assembly 3.3 has a ring-shaped structure, forming an internal accommodating space. The central axis of this accommodating space coincides with the rotation axis of the rotating disk 1.2. The upper surface of the first suction cup assembly 3.3 is an annular first adsorption surface, used to support and adsorb the second-size wafer. The radial width of the first adsorption surface is designed according to the size of the second-size wafer to ensure that it can provide sufficient support area for the second-size wafer.

[0024] The switching module 2 includes a lifting mechanism and a second suction cup assembly 2.8. The second suction cup assembly 2.8 is a disc-shaped structure housed within the internal space of the first suction cup assembly 3.3. The outer diameter of the second suction cup assembly 2.8 is smaller than the inner diameter of the first suction cup assembly 3.3. The second suction cup assembly 2.8 and the first suction cup assembly 3.3 are coaxially aligned but do not contact each other, with an annular gap between them. The width of this annular gap is precisely designed to ensure that the first suction cup assembly 3.3 and the second suction cup assembly 2.8 do not rub or interfere with each other during relative movement, while also minimizing the possibility of dust or particles falling into the gap. The upper surface of the second suction cup assembly 2.8 is a circular second adsorption surface used to support and adsorb a first-size wafer, the size of which is smaller than that of a second-size wafer.

[0025] The lifting mechanism is mounted on the fixed base plate 3.1 and located below the first suction cup assembly 3.3. The lifting mechanism is connected to the bottom of the second suction cup assembly 2.8, and can drive the second suction cup assembly 2.8 to move vertically, thereby adjusting the height of the second suction cup assembly 2.8 relative to the first suction cup assembly 3.3.

[0026] The lifting mechanism specifically includes a lifting base 2.7, a power assembly 2.6, a guide assembly, and a second suction cup holder 2.1. The lifting base 2.7 is a vertically arranged frame structure, and its bottom surface is fixed to the upper surface of the fixed base plate 3.1 with screws. The power assembly 2.6 is located at the bottom or side of the lifting base 2.7 and can be a cylinder, electric cylinder, or linear motor, used to provide the driving force required for the lifting movement. The guide assembly includes a slide rail 2.10 and a slider 2.9. The slide rail 2.10 is fixedly installed vertically on the front side of the lifting base 2.7, and the slider 2.9 is slidably connected to the slide rail 2.10, with a precision sliding fit between them. The second suction cup holder 2.1 is used to fix the second suction cup assembly 2.8, and is fixedly connected to the slider 2.9 via a connecting device 2.11. The drive end of the power component 2.6 is connected to the second suction cup seat 2.1. When the power component 2.6 is activated, it drives the second suction cup seat 2.1 to move up and down along the slide rail 2.10, thereby driving the second suction cup component 2.8 fixed on the second suction cup seat 2.1 to move vertically up and down.

[0027] Furthermore, the lifting mechanism also includes a limiting component 2.2. The limiting component 2.2 is fixed to the lifting base 2.7 and located above the movement path of the slider 2.9. When the slider 2.9 moves upward to the designated position corresponding to the first position, the limiting component 2.2 abuts against the boss on the slider 2.9 or the connecting device 2.11, preventing the slider 2.9 from continuing to move upward, thereby precisely limiting the upward position of the second suction cup assembly 2.8 and ensuring that the second suction cup assembly 2.8 reliably stops at the first position.

[0028] Furthermore, the lifting mechanism also includes a buffer assembly 2.4. The buffer assembly 2.4 is fixed to the lifting base 2.7 and located below the movement path of the slider 2.9. When the slider 2.9 moves downwards and approaches the second position, the lower end of the slider 2.9 first contacts the buffer assembly 2.4. The buffer assembly 2.4 provides damping force to absorb the kinetic energy of the movement, causing the second suction cup assembly 2.8 to decelerate and stop smoothly, avoiding rigid impact between the second suction cup assembly 2.8 and the fixed base plate 3.1 or other components.

[0029] Furthermore, the lifting mechanism also includes a measuring component 2.5. The measuring component 2.5 is mounted on the lifting base 2.7 and is used to detect the lifting distance of the second suction cup assembly 2.8 in real time. The measuring component 2.5 can be an optical encoder, a magnetic encoder, or a laser displacement sensor. The measuring component 2.5 feeds back the detected displacement signal to the control system in real time. The control system then uses the feedback signal to perform closed-loop control of the power component 2.6, achieving high-precision positioning of the lifting position of the second suction cup assembly 2.8.

[0030] The first suction cup assembly 3.3 is connected to the vacuum generator via an independent vacuum line, which provides vacuum adsorption force to the first adsorption surface of the first suction cup assembly 3.3. The second suction cup assembly 2.8 is connected to the vacuum generator via another independent vacuum line, which provides vacuum adsorption force to the second adsorption surface of the second suction cup assembly 2.8. The two sets of vacuum lines are independent of each other and are independently controlled by the control system, so that adsorption can be activated individually or simultaneously according to the needs of the working mode.

[0031] The rotating module 1 includes a rotating base 1.1, a rotating disk 1.2, and a rotating motor. The rotating base 1.1 is fixedly mounted on the equipment base, and the rotating disk 1.2 is rotatably positioned above the rotating base 1.1 about a vertical axis. A fixed base plate 3.1 is fixedly connected to the upper surface of the rotating disk 1.2. The rotating motor is located below or inside the rotating base 1.1, and its output shaft is connected to the rotating disk 1.2 via a transmission connection. When the rotating motor is working, it drives the rotating disk 1.2 to rotate about a vertical axis, thereby causing the fixed module 3 and the switching module 2 to rotate synchronously as a whole. The rotating motor can be a direct-drive motor, with its rotor directly connected to the rotating disk 1.2 to eliminate transmission backlash and improve rotational accuracy.

[0032] The wafer stage has a first operating mode and a second operating mode. Before the inspection process begins, the control system receives the size information of the incoming wafer and controls the wafer stage to enter the corresponding operating mode based on the size information.

[0033] When the incoming material is a first-size wafer, the wafer stage enters the first working mode. In the first working mode, the power component 2.6 of the lifting mechanism drives the second suction cup base 2.1 to move upward along the slide rail 2.10, thereby raising the second suction cup assembly 2.8 to the first position. At the first position, the upper surface of the second suction cup assembly 2.8 is higher than the upper surface of the first suction cup assembly 3.3, and the second adsorption surface of the second suction cup assembly 2.8 is at its highest working height. The robotic arm 4 places the first-size wafer on the second adsorption surface of the second suction cup assembly 2.8, and the control system then activates the vacuum line connected to the second suction cup assembly 2.8, generating a vacuum adsorption force to firmly adsorb and fix the first-size wafer onto the second suction cup assembly 2.8.

[0034] When the incoming material is a second-size wafer, the wafer stage enters the second working mode. In the second working mode, the power component 2.6 of the lifting mechanism drives the second suction cup base 2.1 to move downwards along the slide rail 2.10, thereby causing the second suction cup assembly 2.8 to descend to the second position. In the second position, the upper surface of the second suction cup assembly 2.8 is lower than the upper surface of the first suction cup assembly 3.3, and the second suction cup assembly 2.8 rests below the first suction cup assembly 3.3. The upper surface of the first suction cup assembly 3.3 is fully exposed, forming a complete annular support surface. The robot arm 4 places the second-size wafer on the annular support surface of the first suction cup assembly 3.3, and the control system activates the vacuum line connected to the first suction cup assembly 3.3, generating a vacuum suction force to firmly adhere and fix the second-size wafer to the first suction cup assembly 3.3.

[0035] By precisely setting the heights of the first and second positions, the first horizontal plane containing the upper surface of a first-sized wafer when it is adsorbed onto the second suction cup assembly 2.8 is the same as the second horizontal plane containing the upper surface of a second-sized wafer when it is adsorbed onto the first suction cup assembly 3.3. That is, the height difference between the first and second positions is equal to the thickness difference between the first and second-sized wafers. Therefore, regardless of the operating mode of the wafer stage or the size of the wafer being adsorbed, the upper surface of the wafer remains at the same horizontal plane, and the working distance of the optical inspection lens remains constant, eliminating the need for any height adjustments or recalibration due to changes in wafer size.

[0036] In practical applications, the first size wafer is a 6-inch wafer, and the second size wafer is an 8-inch wafer. When the 6-inch wafer is adsorbed, its upper surface is in the exact same position as when the 8-inch wafer is adsorbed, thus meeting the requirements of silicon carbide substrates and epitaxial detection processes for compatible detection of both 8-inch and 6-inch wafers.

[0037] Both the upper surfaces of the first suction cup assembly 3.3 and the second suction cup assembly 2.8 are provided with annular grooves or arrays of suction holes for uniformly distributing vacuum adsorption force. The annular grooves are several concentric annular grooves machined on the first and second adsorption surfaces, with the bottom of each groove connected to a corresponding vacuum line via radial holes. The array of suction holes consists of multiple micro-holes uniformly distributed on the first and second adsorption surfaces, each hole connected to a corresponding vacuum line. When the vacuum line is open, the vacuum adsorption force is uniformly transmitted to the lower surface of the wafer through the annular grooves or array of suction holes, ensuring uniform force on the wafer and preventing wafer deformation or markings due to excessive local adsorption force.

[0038] In one specific embodiment, the adsorption surfaces of the first suction cup assembly 3.3 and the second suction cup assembly 2.8 are composite adsorption structures. This composite adsorption structure simultaneously possesses a vacuum adsorption channel and an electrostatic adsorption electrode. The vacuum adsorption channel is an annular groove or array of adsorption holes disposed on the adsorption surface and connected to a corresponding vacuum pipeline; the electrostatic adsorption electrode is embedded inside the adsorption surface, and the electrode is made of conductive material, with its surface flush with or slightly lower than the adsorption surface. The electrostatic adsorption electrode is connected to an external high-voltage power supply via wires. The control system selectively controls the operating states of vacuum adsorption and electrostatic adsorption according to the wafer type, thickness, and process requirements. For example, for ultrathin wafers, electrostatic adsorption can be initiated first to adsorb and flatten the wafer, followed by vacuum adsorption to provide a stable composite adsorption force; for wafers with intricate patterns on the back side that are not suitable for direct large-area contact with the adsorption surface, only electrostatic adsorption can be used to avoid localized marks or contamination on the back side of the wafer caused by the vacuum adsorption holes; for severely warped wafers, electrostatic adsorption force can be used to flatten them first, followed by vacuum adsorption, to ensure the wafer remains flat throughout the entire inspection process.

[0039] In one specific embodiment, a repeatable positioning structure is provided between the bottom surface of the first suction cup assembly 3.3 and the top surface of the support column 3.2, and between the bottom surface of the second suction cup assembly 2.8 and the second suction cup base 2.1. This repeatable positioning structure includes a positioning pin and a positioning bushing. The positioning pin is fixed to the top surface of the support column 3.2 or the top surface of the second suction cup base 2.1, and the positioning bushing is fitted into the corresponding position on the bottom surface of the first suction cup assembly 3.3 or the bottom surface of the second suction cup assembly 2.8. When the first suction cup assembly 3.3 or the second suction cup assembly 2.8 needs to be removed for cleaning or replaced due to wafer fragment damage, the suction cup assembly can be removed by unscrewing the screws. During reinstallation, the positioning bushing on the bottom surface of the suction cup assembly is aligned with the positioning pin and inserted, quickly and accurately restoring the installation position of the suction cup assembly without the need for complex position calibration, saving equipment maintenance time.

[0040] In one specific embodiment, the first suction cup assembly 3.3 is connected to the support column 3.2, and the second suction cup assembly 2.8 is connected to the second suction cup base 2.1, both via a magnetic quick-lock mechanism or a snap-lock mechanism. The magnetic quick-lock mechanism includes a permanent magnet embedded in the top surface of the support column 3.2 or the top surface of the second suction cup base 2.1, and a ferromagnetic block embedded in the bottom surface of the first suction cup assembly 3.3 or the bottom surface of the second suction cup assembly 2.8. The magnetic attraction between the permanent magnet and the ferromagnetic block is sufficient to reliably lock the suction cup assembly. The snap-lock mechanism includes a hook on the bottom surface of the suction cup assembly and a slot on the top surface of the support component, achieving locking and unlocking through rotation or pressing. With this connection method, operators can quickly disassemble and install the suction cup assembly without using screwdrivers or wrenches, significantly improving maintenance efficiency.

[0041] In one specific embodiment, the support column 3.2 is made of Invar steel or glass-ceramic. Invar steel is an iron-nickel alloy with an extremely low coefficient of thermal expansion; glass-ceramic is obtained through a controlled crystallization process and also has a near-zero coefficient of thermal expansion. The support column 3.2 has through-holes extending axially, filled with a phase change material, such as paraffin wax, fatty acids, or inorganic salt hydrates. A flexible thermal insulation pad is provided between the bottom of the support column 3.2 and the fixed base plate 3.1. This flexible thermal insulation pad is made of a high-temperature resistant polymer or inorganic fiber material with low thermal conductivity. During the operation of the wafer stage, the rotating motor generates heat or ambient temperature fluctuations cause thermal expansion of the components. When the temperature rises, the phase change material absorbs heat and undergoes a solid-liquid phase change, storing a large amount of heat as latent heat while its own temperature remains almost constant, thus slowing down the temperature rise rate of the support column 3.2. Meanwhile, Invar or microcrystalline glass itself has an extremely low coefficient of thermal expansion. Combined with the bottom flexible heat insulation pad to block heat conduction from the fixed base plate 3.1, the thermal deformation of the support column 3.2 in the height direction is effectively suppressed. The thermal drift of the first adsorption surface height of the first suction cup assembly 3.3 is controlled within a very small range throughout the entire detection cycle, ensuring the stability of the wafer surface height during continuous detection.

[0042] In one specific embodiment, both the outer periphery of the second suction cup assembly 2.8 and the inner periphery of the first suction cup assembly 3.3 are provided with rounded chamfers. The rounded chamfers extend continuously along the periphery, and the radius of the rounded chamfers is designed according to the thickness and material of the wafer. The surface of the rounded chamfers is polished to make the surface roughness Ra value of the chamfer area sufficiently low, forming a smooth transition surface. When the robot arm 4 places the wafer on the first suction cup assembly 3.3 or the second suction cup assembly 2.8, even if the edge of the wafer contacts the periphery of the suction cup assembly first during the descent, the smooth rounded surface can guide the wafer to slide smoothly into the predetermined position, avoiding hard contact between the sharp edge and the wafer edge, which could cause the wafer edge to break or generate microcracks, effectively protecting the integrity of wafers made of brittle materials such as silicon carbide.

[0043] In one specific embodiment, the guide assembly employs a cross-roller slide rail structure. The cross-roller slide rail has cross-arranged cylindrical rollers between the slide rail 2.10 and the slider 2.9, with the roller axes alternating at 90-degree angles. A preload spring is provided between the slider 2.9 and the slide rail 2.10, continuously applying preload to the slider 2.9 to ensure the rollers maintain close contact with the rolling surface of the slide rail 2.10. This structure eliminates backlash during movement. When the lifting mechanism drives the second suction cup assembly 2.8 to rise and fall, even if the direction of movement changes, there will be no displacement error caused by backlash. Simultaneously, it provides high-rigidity guide support, significantly improving the smoothness and positioning accuracy of the lifting movement of the second suction cup assembly 2.8.

[0044] In one specific embodiment, the connection between the rotating disk 1.2 and the fixed base plate 3.1 is provided with an annular guide groove and a ball bearing assembly. The annular guide groove is coaxially formed on the upper surface of the rotating disk 1.2, and the ball bearing assembly is embedded in the annular guide groove and fits against the lower surface of the fixed base plate 3.1. The cross-sectional shape of the annular guide groove is arc-shaped or V-shaped. The ball bearing assembly consists of multiple precision steel balls or ceramic balls, embedded in the annular guide groove, with the upper part of the balls fitting against the lower surface of the fixed base plate 3.1. When the rotating disk 1.2 drives the fixed base plate 3.1 to rotate, the balls roll in the annular guide groove, acting as a planar thrust bearing to provide stable circumferential support for the fixed base plate 3.1. A torque sensor and a reduction and buffer mechanism are provided on the output shaft of the rotary motor. The torque sensor is used to monitor the output torque of the rotary motor in real time, and the control system determines whether there is abnormal resistance during the rotation process based on the torque feedback value. The deceleration and buffer mechanism is located between the output end of the rotary motor and the rotating disk 1.2. The deceleration and buffer mechanism can adopt a flexible coupling or a hydraulic damper to slow down the rapid change of speed when the rotating module 1 starts and stops, avoid the instantaneous shaking of the rotating disk 1.2 and the fixed module 3 caused by the impact, and ensure that the wafer is always stably within the optimal detection range of the optical inspection lens during the rotation process.

[0045] In one specific embodiment, the support column 3.2 is a telescopic structure. The support column 3.2 includes a fixed section and a telescopic section. The fixed section is located at the bottom, and its bottom end is fixedly connected to the fixed base plate 3.1. The telescopic section is located at the top, and its top end is fixedly connected to the first suction cup assembly 3.3. The telescopic section is slidably fitted inside or outside the fixed section, and the total height of the support column 3.2 is changed by adjusting the length of the telescopic section extending beyond the fixed section. A locking bolt is provided on the telescopic section; after the telescopic section is adjusted to the target height, tightening the locking bolt locks the position of the telescopic section relative to the fixed section. A height scale line is provided on the outer surface of the support column 3.2, which is engraved along the axial direction of the support column 3.2 to visually display the current height value of the support column 3.2 during adjustment. Based on the levelness detection results of the first suction cup assembly 3.3, the operator can adjust the height of each support column 3.2 individually to compensate for minor tilting caused by equipment installation errors or foundation settlement, ensuring that the levelness of the working plane of the first suction cup assembly 3.3 meets the stringent requirements of precision testing.

[0046] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, nor is it limited to wafer carriers. Devices and structures not described in detail herein should be understood as being implemented in a manner common to the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, still fall within the protection scope of the present invention.

Claims

1. A wafer carrier, characterized in that, Includes a fixed module, a switching module, and a rotating module; The fixing module includes a fixing base plate, a support column, and a first suction cup assembly; the fixing base plate is connected to the rotating module, the support column is fixed on the fixing base plate, and the first suction cup assembly is fixed above the fixing base plate through the support column. The first suction cup assembly has a ring structure and forms an accommodating space inside. The switching module includes a lifting mechanism and a second suction cup assembly. The second suction cup assembly is a disc-shaped structure, located within the accommodating space of the first suction cup assembly, and its outer diameter is smaller than the inner diameter of the first suction cup assembly. The second suction cup assembly and the first suction cup assembly are coaxially arranged and do not contact each other. The lifting mechanism is located on a fixed base plate and connected to the bottom of the second suction cup assembly. The lifting mechanism can drive the second suction cup assembly to move in the vertical direction. The wafer stage has a first operating mode and a second operating mode; In the first working mode, the lifting mechanism drives the second suction cup assembly to rise to the first position. The upper surface of the second suction cup assembly is higher than the upper surface of the first suction cup assembly, which is used to support and adsorb and fix the first size wafer. In the second working mode, the lifting mechanism drives the second suction cup assembly to descend to the second position. The upper surface of the second suction cup assembly is lower than the upper surface of the first suction cup assembly. The upper surface of the first suction cup assembly forms an annular bearing surface for bearing and adsorbing and fixing the second-sized wafer. When the first-sized wafer is adsorbed onto the second suction cup assembly, the first horizontal plane on which its upper surface is located is the same horizontal plane as the second-sized wafer on which its upper surface is located when it is adsorbed onto the first suction cup assembly.

2. The wafer stage according to claim 1, characterized in that, The lifting mechanism includes a lifting base, a power component, a guide component, and a second suction cup seat. The lifting base is fixed to a fixed base plate. The power component is mounted on the lifting base. The guide component includes a slide rail and a slider. The slide rail is fixed to the lifting base, and the slider is slidably connected to the slide rail. The second suction cup seat is connected to the slider and is fixedly connected to the second suction cup assembly. The power component is connected to the second suction cup seat and is used to drive the second suction cup seat and the second suction cup assembly to move up and down along the slide rail.

3. The wafer stage according to claim 2, characterized in that, The lifting mechanism also includes a limiting component, which is disposed on the lifting base and located above the slider, and is used to limit the slider when it moves to the first position.

4. The wafer stage according to claim 2, characterized in that, The lifting mechanism also includes a buffer assembly, which is mounted on the lifting base and located below the slider, to provide cushioning when the slider moves downward.

5. The wafer stage according to claim 2, characterized in that, The lifting mechanism also includes a measuring component, which is mounted on the lifting base and is used to measure the lifting distance of the second suction cup assembly.

6. The wafer stage according to claim 1, characterized in that, The first suction cup assembly is connected to the vacuum generator via a separate vacuum line, and the second suction cup assembly is connected to the vacuum generator via another separate vacuum line.

7. The wafer stage according to claim 1, characterized in that, The rotating module includes a rotating base, a rotating disk, and a rotating motor; the fixed base plate is fixedly connected to the rotating disk, and the rotating motor is used to drive the rotating disk to rotate, thereby driving the fixed module and the switching module to rotate synchronously.

8. The wafer stage according to claim 1, characterized in that, The first size wafer is a 6-inch wafer, and the second size wafer is an 8-inch wafer.

9. The wafer stage according to claim 1 or 6, characterized in that, The upper surface of the first suction cup assembly and / or the upper surface of the second suction cup assembly are provided with annular grooves or an array of suction holes for distributing vacuum suction force.

10. The wafer stage according to claim 1, characterized in that, The adsorption surfaces of the first and second suction cup assemblies are composite adsorption structures, possessing both vacuum adsorption channels and electrostatic adsorption electrodes, enabling them to apply vacuum adsorption force, electrostatic adsorption force, or a combination of both to the wafer.

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