Double-layer station wafer aligner

Abstract

The invention discloses a double-layer station wafer aligner which comprises a connecting base, a first base, a second base and a connecting frame, the first base and the second base are arranged in an up-down layered mode, the first base is located below the second base, and the first base and the second base are both installed on the connecting base; the first base and the second base are provided with a first containing table and a second containing table which are independently driven in a rotating mode respectively. The first base and the second base are further provided with a first edge searching sensor and a second edge searching sensor. By the adoption of the double-layer station design, compared with an existing aligner, space is saved for the using environment. Secondly, pre-positioning of the wafer is facilitated through arrangement of the positioning mechanism, so that deviation of the wafer during edge searching calibration is avoided; meanwhile, due to dual-mode switching of air floatation lifting and negative pressure adsorption, wafer damage is avoided, and high-speed rotation stability is ensured.

Description

Technical Field

[0001] The present application relates to a wafer aligner, and more specifically, to a double-layer workstation wafer aligner, belonging to the technical field of wafer alignment. Background Art

[0002] Wafer aligner is a key equipment in the semiconductor and MEMS manufacturing lithography process. It acquires the mask and wafer alignment mark images through optical imaging, calculates the deviation through image processing, and then adjusts the position by a high-precision mechanical motion platform to achieve precise alignment. Its key components include the alignment optical system, motion control platform and image processing unit. Its technical indicators cover alignment accuracy, production efficiency, and applicable wafer size. It is used in integrated circuit and MEMS manufacturing to meet the needs of precise pattern transfer.

[0003] The existing technology achieves multi-wafer synchronous alignment by adding multiple edge-finding sensors and motor axes in a plane. However, the multi-sensor layout easily leads to an increase in the size of the optical system, which not only increases the space cost of the clean room, but also introduces additional aberrations due to the increase in the optical path; secondly, each sensor needs to be equipped with an independent servo motor and reading head, which increases the manufacturing cost of the motion platform. Summary of the invention

[0004] The present application provides a double-layer workstation wafer aligner to solve the technical problem in the related art that the multi-sensor layout easily leads to an increase in the volume of the optical system, which not only increases the space occupation cost of the clean room, but also introduces additional aberrations due to the increase in the optical path, thereby increasing the manufacturing cost of the motion platform.

[0005] The present application provides a double-layer workstation wafer aligner, comprising a connecting seat, a first base and a second base arranged in upper and lower layers, and a connecting frame, wherein the first base is located below the second base, and the first base and the second base are both installed on the connecting seat; the first base and the second base are respectively provided with a first placement table and a second placement table independently driven for rotation, and a first wafer and a second wafer are respectively placed on the first placement table and the second placement table, and the first placement table and the second placement table are staggered so that the placement positions of the first wafer and the second wafer form a cross avoidance; a first edge-finding sensor and a second edge-finding sensor are also installed on the first base and the second base, and a dual-wafer alignment operation is realized by synchronously controlling the rotation action of the first rotating motor and the second rotating motor.

[0006] As a further optimization scheme of the present application, a positioning mechanism is provided inside the second base, and the positioning mechanism includes a connecting shaft, and the connecting shaft is symmetrically arranged inside the second base. Connecting plates are installed at both ends of the connecting shaft, and rotating shafts are symmetrically provided on the connecting plates, and positioning rollers are installed on the rotating shafts. A third rotating motor is also installed inside the second base, and a driving shaft is installed at the output shaft of the third rotating motor, a winding disk is provided on the driving shaft, and pull ropes are symmetrically installed on the winding disk, and the end of the pull rope away from the winding disk is fixedly connected to the connecting shaft, and rubber pulleys are provided on both sides of the pull rope.

[0007] As a further optimization scheme of the present application, a sliding groove corresponding to the position of the connecting shaft is opened on the second base, and both ends of the connecting shaft extend through the sliding groove to the outer surface of the second base. A spring is provided inside the sliding groove, and one end of the spring is fixedly connected to the sliding groove, and the other end of the spring is fixedly connected to the connecting shaft.

[0008] As a further optimization scheme of the present application, a first air supply disk is provided on the outside of the driving shaft, and the first air supply disk is installed on the third rotating motor, a first air cavity is opened inside the driving shaft, and a plurality of air ports are also opened on the driving shaft, an air bag is provided between the driving shaft and the winding disk, and the air bag is installed on the driving shaft, and the air ports are respectively connected with the first air supply disk and the interior of the air bag.

[0009] As a further optimization solution of the present application, a plurality of protrusions are installed in a ring shape inside the winding disk, and when the airbag is inflated, the protrusions engage with the protrusions inside the winding disk to enhance the friction transmission between the drive shaft and the winding disk.

[0010] As a further optimization scheme of the present application, the first rotating motor and the second rotating motor are respectively installed on the first base and the second base, the first placing table is connected to the output shaft of the first rotating motor, the second placing table is connected to the output shaft of the second rotating motor, and the first placing table and the second placing table are provided with an air floating lifting mechanism.

[0011] As a further optimization scheme of the present application, the air flotation lifting mechanism includes a plurality of first air holes opened on the upper surfaces of the first placing table and the second placing table, a plurality of second air holes opened in a ring shape on the columnar surfaces of the first placing table and the second placing table, and a second air supply disk and an air pump; the air pump is provided with two first connecting ends and one second connecting end; the two first connecting ends on the air pump are connected to a third connecting pipe, and the end of the third connecting pipe away from the air pump is connected to the second air supply disk, the third connecting pipe is connected to the interior of the second air supply disk, and the second connecting end of the air pump is connected to the second connecting pipe.

[0012] As a further optimization solution of the present application, the air pump has an air floating lifting mode and a negative pressure locking mode, which respectively exhaust air through the first air hole to form an air film or absorb air to adsorb the wafer.

[0013] As a further optimization scheme of the present application, the second connecting end of the air pump is connected to the second connecting tube of the positioning mechanism, so that the air pump synchronously drives the airbag to expand in the negative pressure locking mode. When the air pump switches to the negative pressure locking mode, the airbag expansion pressure is positively correlated with the adsorption negative pressure value of the first wafer and the second wafer, and the engagement depth of the airbag and the bump increases linearly with the increase of the air pressure value.

[0014] As a further optimization scheme of the present application, a switching mechanism and a backup edge-finding sensor are provided in the first base and the second base, and the switching mechanism and the backup edge-finding sensor correspond to the positions of the first edge-finding sensor and the second edge-finding sensor. The first edge-finding sensor and the second edge-finding sensor are controlled by the switching mechanism to rotate 180° to switch and enable the backup edge-finding sensor.

[0015] The beneficial effects of the present application are as follows: the present application adopts a double-layer workstation design, which saves space for the use environment compared to the existing aligner; and, only one set of control system is used to achieve multi-wafer alignment at the same time, reducing the cost of aligning multiple wafers at the same time for users. Secondly, the setting of the positioning mechanism facilitates the pre-positioning of the wafer to avoid deviation of the wafer during edge-finding calibration; at the same time, the dual-mode switching of air flotation lifting and negative pressure adsorption avoids wafer damage and ensures high-speed rotation stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of Example 1 in this application; Figure 2 It is a schematic diagram of the partial explosion structure of Example 1 in the present application; Figure 3 It is a perspective schematic diagram of the three-dimensional structure of Example 1 in the present application; Figure 4 It is a schematic diagram of the three-dimensional structure of Example 2 in this application; Figure 5 It is a schematic diagram of a partial three-dimensional structure of Example 2 in the present application; Figure 6 It is the second embodiment of the present application. Figure 5 A magnified view of the structure at center; Figure 7 It is a schematic diagram of the three-dimensional structure of the positioning mechanism of Example 2 in the present application; Figure 8 It is the second embodiment of the present application. Figure 7 A magnified view of the structure at B in the middle; Fig. 9It is a three-dimensional cross-sectional structural diagram of the third rotating motor, the driving shaft, the winding disk and the first air supply disk of the second embodiment of the present application; Fig.10 Schematic diagram of the position relationship between the drive shaft, winding disc and airbag in the second embodiment of the present application; Fig.11 It is a schematic diagram of the internal structure of the second embodiment of the present application; Fig.12 It is the second embodiment of the present application. Fig.11 A magnified view of the structure at C in the middle; Fig.13 It is a schematic diagram of the three-dimensional structure of the air floating lifting mechanism of the second embodiment of the present application; Fig.14 It is a schematic diagram of the three-dimensional structure of the switching mechanism of Example 3 in the present application; In the figure: 1, connecting seat; 2, first base; 3, second base; 4, connecting frame; 5, first rotating motor; 6, first placement table; 7, second rotating motor; 8, second placement table; 9, first edge-finding sensor; 10, second edge-finding sensor; 11, first light source; 12, second light source; 13, first wafer; 14, second wafer; 15, positioning mechanism; 151, connecting shaft; 152, connecting plate; 153, rotating shaft; 154, positioning roller; 155, third rotating motor; 156, driving shaft; 157, winding disk; 158, pull rope; 159, pulley; 1510, slide groove; 1511, spring; 151 2. Guide rail; 1513. First air supply disk; 1514. First annular slider; 1515. First air cavity; 1516. Air port; 1517. Air bag; 1518. First connecting pipe; 1519. One-way valve; 1520. Bump; 1521. Second connecting pipe; 16. Air floating lifting mechanism; 161. First air hole; 162. Second air hole; 163. Second air supply disk; 164. Air pump; 165. Third connecting pipe; 166. Second air cavity; 167. Second annular slider; 17. Switching mechanism; 171. Switching shaft; 172. Switching flap; 173. Electric push rod; 174. Rack plate; 175. Gear. DETAILED DESCRIPTION

[0017] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Each example may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0018] Embodiment 1 This embodiment aims to provide a double-layer workstation wafer aligner, which saves valuable space for the use environment and saves the cost of aligning multiple wafers at the same time for users. Among them, the wafer alignment sensor is mainly based on the principle of optical imaging, using an optical lens to collect the alignment mark images on the wafer and mask, and calculating the deviation through the image processing algorithm, the electron beam detection principle to emit an electron beam to scan the wafer, and determine the deviation of the mark position according to the electronic signal, or the laser interference principle to calculate the wafer deviation according to the change of the interference fringe based on the laser interference characteristics to achieve high-precision position detection and alignment.

[0019] according to Figure 1 , Figure 2 and Figure 3 As shown, a double-layer workstation wafer aligner provided in this embodiment includes a connecting base 1, a first base 2, a second base 3 and a connecting frame 4, the first base 2, the second base 3 and the connecting frame 4 are all installed on the connecting base 1, and the first base 2 and the second base 3 are divided into two layers, an upper layer and an lower layer; wherein the first base 2 is located below the second base 3, and the second base 3 is located above the first base 2.

[0020] Specifically, a first rotating motor 5 is mounted on the first base 2, and a first placing table 6 is mounted on the output shaft of the first rotating motor 5, a first wafer 13 is placed on the first placing table 6, and a first edge-finding sensor 9 is also mounted on the first base 2, and the first edge-finding sensor 9 is used to detect the edge of the first wafer 13; a second rotating motor 7 is mounted on the second base 3, and a second placing table 8 is mounted on the output shaft of the second rotating motor 7, a second wafer 14 is placed on the second placing table 8, and a second edge-finding sensor 10 is also mounted on the second base 3, and the second edge-finding sensor 10 is used to detect the edge of the second wafer 14. In addition, a first light source 11 and a second light source 12 are mounted on the connecting frame 4, and the positions of the first light source 11 and the second light source 12 correspond to the positions of the first edge-finding sensor 9 and the second edge-finding sensor 10 respectively; a penetration groove is opened on the second base 3, and the first light source 11 passes through the penetration groove to supplement light for the first wafer 13, and the second light source 12 is used to supplement light for the second wafer 14.

[0021] It should be noted that according to Figure 3 As shown, the first rotary motor 5 and the first placement table 6 are staggered with the second rotary motor 7 and the second placement table 8, so that the positions of the first wafer 13 and the second wafer 14 on the wafer aligner are crossed, thereby facilitating fill light and edge finding operations.

[0022] When the double-layer workstation wafer aligner is working, the first wafer 13 and the second wafer 14 can be placed on the upper surfaces of the first placement table 6 and the second placement table 8 respectively, and the wafer aligner is controlled to turn on the first light source 11 and the second light source 12 to provide fill light for the first wafer 13 and the second wafer 14. The first edge-finding sensor 9 and the second edge-finding sensor 10 work simultaneously to judge the positions of the first wafer 13 and the second wafer 14 and transmit the position information of the first wafer 13 and the second wafer 14 to the central processing unit. The central processing unit sends a signal to control the first rotating motor 5 and the second rotating motor 7 to rotate, thereby driving the first placement table 6 and the second placement table 8 to rotate to align the wafers.

[0023] When placing the first wafer 13 and the second wafer 14 on the upper surfaces of the first placement table 6 and the second placement table 8 respectively, a wafer transport robot may be used.

[0024] What needs to be understood here is that wafer handling robots are key equipment in semiconductor manufacturing, including vacuum manipulators that use the principle of vacuum adsorption, adapt to a variety of wafer sizes and have little damage, articulated robots that imitate human arm joints and have high flexibility to cope with complex path handling, and track-type robots that run along preset tracks and have high stability and positioning accuracy. In addition, wafer handling robots integrate key technologies such as high-precision positioning, motion control, and cleanliness, and have the characteristics of high automation, high efficiency, and high reliability. They are widely used in the full-process inter-process handling of wafer manufacturing workshops, as well as the material transfer from wafer cutting to chip packaging in the chip packaging process, which is of great significance to improving semiconductor production efficiency and product quality.

[0025] In summary, this embodiment adopts a double-layer workstation design, which saves space for the use environment compared to existing aligners; and only uses one set of control system to achieve multi-wafer alignment at the same time, reducing the cost of users aligning multiple wafers at the same time.

[0026] Embodiment 2 according to Figure 4 and Figure 5 As shown, a positioning mechanism 15 is added on the basis of the first embodiment. The positioning mechanism 15 is arranged inside the second base 3 and is used for pre-clamping and positioning the first wafer 13 and the second wafer 14 .

[0027] according to Figure 6 , Figure 7 and Figure 8As shown, the positioning mechanism 15 in this embodiment includes a connecting shaft 151, which is symmetrically arranged inside the second base 3. Connecting plates 152 are installed at both ends of the connecting shaft 151. Rotating shafts 153 are symmetrically arranged on the connecting plates 152, and the rotating shaft 153 is connected to the connecting plates 152 by bearings. A positioning roller 154 is installed on the rotating shaft 153, and an annular groove is provided on the positioning roller 154. A third rotating motor 155 is also installed inside the second base 3, and a driving shaft 156 is installed at the output shaft of the third rotating motor 155. A winding disk 157 is provided on the driving shaft 156, and a pull rope 158 is symmetrically installed on the winding disk 157. The end of the pull rope 158 away from the winding disk 157 is fixedly connected to the connecting shaft 151, and the winding disk 157 is rotatably connected to the inside of the second base 3 through a bearing.

[0028] It should be understood that when the third rotating motor 155 drives the winding disk 157 to rotate, the winding disk 157 drives the pull rope 158 to perform a winding operation, thereby pulling the connecting plate 152 to move the connecting plate 152 away from the first wafer 13 and the second wafer 14, and resetting the connecting plate 152 to facilitate the next positioning work.

[0029] Among them, pulleys 159 are provided on both sides of the outside of the pull rope 158 to provide sliding support for the pull rope 158 through the pulleys 159. The pulleys 159 are connected to the inner wall bearing of the second base 3. The pulleys 159 are made of rubber, thereby increasing the damping of the pull rope 158 and slowing down the release of the pull rope 158.

[0030] Specifically, a slide groove 1510 corresponding to the position of the connecting shaft 151 is opened on the second base 3, and both ends of the connecting shaft 151 extend through the slide groove 1510 to the outer surface of the second base 3, and the connecting shaft 151 is slidably limited by the slide groove 1510; and, a guide rail 1512 is slidably connected to the connecting plate 152, and the guide rail 1512 is installed on the outer wall of the second base 3. The setting of the guide rail 1512 improves the stability of the movement of the connecting plate 152; a spring 1511 is provided inside the slide groove 1510, and one end of the spring 1511 is fixedly connected to the slide groove 1510, and the other end of the spring 1511 is fixedly connected to the connecting shaft 151. Through the setting of the spring 1511, the connecting shaft 151 is moved and pulled, so that the two groups of connecting plates 152 can perform positioning operations on the first wafer 13 and the second wafer 14.

[0031] Among them, according to Fig. 9 and Fig.10As shown, a first air supply disk 1513 is provided on the outside of the driving shaft 156, and the first air supply disk 1513 is installed on the third rotating motor 155. The first air supply disk 1513 is internally slidably connected with a first annular slider 1514, and the first annular slider 1514 is installed on the outer wall of the driving shaft 156. Through the sliding connection between the first air supply disk 1513 and the first annular slider 1514, the first air supply disk 1513 facilitates the continuous supply of gas to the rotating driving shaft 156.

[0032] It should be noted that a first air cavity 1515 is provided inside the drive shaft 156, and a plurality of air ports 1516 are also provided on the drive shaft 156. The interiors of the first air cavity 1515 and the air ports 1516 are communicated with each other. An airbag 1517 is provided between the drive shaft 156 and the winding disk 157, and the airbag 1517 is installed on the drive shaft 156. The air ports 1516 are communicated with the interiors of the first air supply disk 1513 and the airbag 1517 respectively. When the first air supply disk 1513 supplies air to the drive shaft 156, the gas enters the first air cavity 1515 from the air port 1516, and is then discharged from the air port 1516 at the airbag 1517, causing the airbag 1517 to expand, thereby increasing the friction between the drive shaft 156 and the winding disk 157, so that the drive shaft 156 drives the winding disk 157 to rotate.

[0033] Furthermore, a plurality of protrusions 1520 are installed in a ring shape inside the winding disk 157. When the airbag 1517 expands, the friction between the winding disk 157 and the airbag 1517 is increased, and the airbag 1517 is expanded to engage with the protrusions 1520, thereby facilitating the winding disk 157 to rotate and improving stability.

[0034] It should be noted that a first connecting pipe 1518 is installed on the first gas supply disk 1513 , and a one-way valve 1519 is installed on the first connecting pipe 1518 . A second connecting pipe 1521 is also installed on the first gas supply disk 1513 .

[0035] The working principle of the double-layer workstation wafer aligner in this embodiment is mainly as follows: when the airbag 1517 is in a contracted state, the winding disk 157 rotates outside the driving shaft 156 to release the pull rope 158, so that under the action of the elastic force of the spring 1511, the movement of the connecting shaft 151 is pulled, thereby driving the connecting plate 152 to move, so that the positioning roller 154 moves toward the first wafer 13 and the second wafer 14 to position the first wafer 13 and the second wafer 14.

[0036] according to Fig.11 , Fig.12 and Fig.13As shown, an air flotation lifting mechanism 16 is provided on the first placement table 6 and the second placement table 8, and the air flotation lifting mechanism 16 includes a first air hole 161, a second air hole 162, a second air supply disk 163 and an air pump 164. There are multiple first air holes 161 and second air holes 162. Multiple first air holes 161 are opened on the upper surface of the first placement table 6 and the second placement table 8, and multiple second air holes 162 are opened in a ring shape on the cylindrical surface of the first placement table 6 and the second placement table 8; the second air supply disk 163 is installed on the outer casing of the first rotating motor 5 and the second rotating motor 7, and the second air supply disk 163 is located outside the output shaft of the first rotating motor 5 and the second rotating motor 7; the air pump 164 is installed on the connecting seat 1.

[0037] Specifically, the air pump 164 is provided with two first connection ends and one second connection end; the two first connection ends on the air pump 164 are connected to the third connecting pipe 165, and the end of the third connecting pipe 165 away from the air pump 164 is connected to the second air supply disk 163, the third connecting pipe 165 is connected to the interior of the second air supply disk 163, and the second connection end of the air pump 164 is connected to the second connecting pipe 1521.

[0038] Among them, the interior of the first placing table 6 and the second placing table 8 are both provided with a second air cavity 166, and the second air cavity 166 is connected with the interior of the first air hole 161 and the second air hole 162, the interior of the second air supply disk 163 is slidably connected with a second annular slider 167, and the second annular slider 167 is respectively installed on the first placing table 6 and the second placing table 8, and the second air supply disk 163 is provided with an opening, which is connected with the interior of the second air cavity 166, so as to facilitate air supply treatment to the first placing table 6 and the second placing table 8 when the first placing table 6 and the second placing table 8 rotate.

[0039] It should be noted that the air pump 164 has two working modes, one is an air floating lifting mode, and the other is a negative pressure locking mode.

[0040] The specific working principle is mainly as follows: when the air pump 164 is in the air flotation lifting mode, the air pump 164 drives the second connection end to inhale air, and the first connection end to blow air outward, so that the airbag 1517 is in a contracted state, and the one-way valve 1519 takes in air in one direction, and discharges the gas from the first air hole 161 and the second air hole 162. When the first wafer 13 and the second wafer 14 are placed on the upper surface of the first placement table 6 and the second placement table 8, the first air hole 161 exhausts air outward to form a support for the bottom of the first wafer 13 and the second wafer 14, thereby preventing the first wafer 13 and the second wafer 14 from directly contacting the front of the first placement table 6 and the second placement table 8, causing the first wafer 13 and the second wafer 14 to collide.

[0041] When the air pump 164 is in the negative pressure locking mode, the air pump 164 drives the first connection end to inhale air and the second connection end to blow air outward, so that the airbag 1517 is inflated, and the first air hole 161 and the second air hole 162 inhale air inward. When the first wafer 13 and the second wafer 14 are placed on the upper surface of the first placement table 6 and the second placement table 8, the first air hole 161 inwardly inhales air, and a negative pressure attraction is formed on the bottom of the first wafer 13 and the second wafer 14, so that the first wafer 13 and the second wafer 14 are adsorbed and fixed, so as to facilitate the rotation operation of the first wafer 13 and the second wafer 14.

[0042] The other features of the second embodiment are the same as those of the first embodiment.

[0043] Embodiment 3 Wafer manufacturing is a highly continuous and time-sensitive process. When the first edge-finding sensor 9 and the second edge-finding sensor 10 are used for a long time and their accuracy decreases, if not handled in time, it may cause edge-finding errors, making it impossible for subsequent processes to proceed normally, and even causing the wafer to be scrapped.

[0044] according to Fig.11 and Fig.14 As shown, a switching mechanism 17 is added on the basis of the first embodiment, and the switching mechanism 17 is arranged at the positions of the first edge-finding sensor 9 and the second edge-finding sensor 10. When used for a long time, the first edge-finding sensor 9 and the second edge-finding sensor 10 are switched by controlling the switching mechanism 17, so that the backup edge-finding sensor works, thereby maintaining the accuracy of detection.

[0045] Secondly, the spare edge-finding sensor can be put into use immediately, avoiding long downtime due to waiting for maintenance or replacement of the first edge-finding sensor 9 and the second edge-finding sensor 10, thereby ensuring continuous operation of the production line.

[0046] Specifically, the switching mechanism 17 includes a switching cavity opened inside the first base 2 and the second base 3, and the position of the switching cavity corresponds one-to-one to the first edge-finding sensor 9 and the second edge-finding sensor 10. The internal bearing of the switching cavity is connected to the switching shaft 171, and a switching flap 172 is installed on the switching shaft 171.

[0047] It needs to be explained in detail that the switching flap 172 is fixedly connected to the first edge-finding sensor 9 and the second edge-finding sensor 10 respectively, and spare edge-finding sensors are installed on one side of the two sets of switching flaps 172 away from the first edge-finding sensor 9 and the second edge-finding sensor 10 respectively, and the arrangement of the spare edge-finding sensors corresponds one-to-one to the arrangement of the first edge-finding sensor 9 and the second edge-finding sensor 10 respectively.

[0048] Furthermore, an electric push rod 173 is installed in the switching chamber, and a rack plate 174 is installed at the telescopic end of the electric push rod 173, and a gear 175 is meshedly connected to the rack plate 174, and the gear 175 is installed on the switching shaft 171; when the electric push rod 173 is driven to perform telescopic movement, the rack plate 174 is controlled to move synchronously, and the switching shaft 171 is controlled to rotate through the meshing connection between the rack plate 174 and the gear 175, and the rotation angle of the switching flap 172 is 180°, so as to facilitate the conversion of the first edge-finding sensor 9 or the second edge-finding sensor 10 to the backup edge-finding sensor, and enable the backup edge-finding sensor to perform edge detection on the first wafer 13 and the second wafer 14.

[0049] In summary, by setting a backup edge-finding sensor to form a redundant system, when a problem occurs in the first edge-finding sensor 9 or the second edge-finding sensor 10, the backup edge-finding sensor can be driven to continue working. This fault-tolerant mechanism can effectively reduce the risk of failure of the entire edge-finding device due to a single sensor failure, and improve the overall reliability of the system.

[0050] The other features of the third embodiment are the same as those of the first embodiment.

[0051] An example of the present specific implementation mode is described above, but the present embodiment is not limited to the above-mentioned specific implementation mode, which is merely illustrative and not restrictive. A person skilled in the art may make many forms inspired by the present embodiment, all of which are protected by the present embodiment.

Claims

1. A double-station wafer aligner, characterized in that: include: A connecting seat, a first base and a second base arranged in layers up and down, and a connecting frame, wherein the first base is located below the second base, and the first base and the second base are both installed on the connecting seat; The first pedestal and the second pedestal are respectively provided with a first placement table and a second placement table which are independently driven for rotation, and a first wafer and a second wafer are respectively placed on the first placement table and the second placement table, and the first placement table and the second placement table are staggered so that the placement positions of the first wafer and the second wafer form a cross avoidance; A first edge-finding sensor and a second edge-finding sensor are also installed on the first pedestal and the second pedestal, and a dual wafer alignment operation is achieved by synchronously controlling the rotational motion of the first rotary motor and the second rotary motor.

2. The double-stage wafer aligner according to claim 1, characterized in that: A positioning mechanism is provided inside the second base, and the positioning mechanism includes a connecting shaft, and the connecting shaft is symmetrically arranged inside the second base. Connecting plates are installed at both ends of the connecting shaft, and rotating shafts are symmetrically provided on the connecting plates, and positioning rollers are installed on the rotating shafts. A third rotating motor is also installed inside the second base, and a driving shaft is installed at the output shaft of the third rotating motor, a winding disk is provided on the driving shaft, and pull ropes are symmetrically installed on the winding disk, and one end of the pull rope away from the winding disk is fixedly connected to the connecting shaft, and pulleys are provided on both sides of the pull rope.

3. The double-stage wafer aligner according to claim 2, characterized in that: The second base is provided with a slide groove corresponding to the position of the connecting shaft, and both ends of the connecting shaft extend through the slide groove to the outer surface of the second base. A spring is provided inside the slide groove, and one end of the spring is fixedly connected to the slide groove, and the other end of the spring is fixedly connected to the connecting shaft.

4. The double-stage wafer aligner according to claim 2, characterized in that: A first air supply disk is provided on the outside of the driving shaft and is installed on the third rotating motor. A first air cavity is opened inside the driving shaft. A plurality of air ports are also opened on the driving shaft. An air bag is provided between the driving shaft and the winding disk and is installed on the driving shaft. The air ports are respectively communicated with the first air supply disk and the inside of the air bag.

5. The double-stage wafer aligner according to claim 2, characterized in that: The interior of the winding disk is provided with a plurality of protrusions in an annular shape. When the airbag expands, the protrusions engage with the protrusions inside the winding disk to enhance the friction transmission between the driving shaft and the winding disk.

6. The double-stage wafer aligner according to claim 1, characterized in that: The first base and the second base are respectively mounted with a first rotating motor and a second rotating motor, the first placement table is connected to the output shaft of the first rotating motor, the second placement table is connected to the output shaft of the second rotating motor, and the first placement table and the second placement table are provided with an air floating lifting mechanism.

7. The double-stage wafer aligner according to claim 6, characterized in that: The air-floating lifting mechanism comprises a plurality of first air holes opened on the upper surfaces of the first placing platform and the second placing platform, a plurality of second air holes opened in an annular shape on the columnar surfaces of the first placing platform and the second placing platform, a second air supply disk and an air pump; The air pump is provided with two first connection ends and one second connection end; the two first connection ends on the air pump are connected to a third connecting pipe, and the end of the third connecting pipe away from the air pump is connected to the second air supply disk, the third connecting pipe is connected to the interior of the second air supply disk, and the second connection end of the air pump is connected to the second connecting pipe.

8. The double-stage wafer aligner according to claim 7, characterized in that: The air pump has an air floating lifting mode and a negative pressure locking mode, which respectively exhaust air through the first air hole to form an air film or absorb air to adsorb the wafer.

9. The double-stage wafer aligner according to claim 7, characterized in that: The second connection end of the air pump is connected to the second connection tube of the positioning mechanism, so that the air pump synchronously drives the airbag to expand in the negative pressure locking mode. When the air pump switches to the negative pressure locking mode, the airbag expansion pressure is positively correlated with the adsorption negative pressure value of the first wafer and the second wafer, and the engagement depth of the airbag and the bump increases linearly with the increase of the air pressure value.

10. The double-stage wafer aligner according to claim 1, characterized in that: A switching mechanism and a backup edge-finding sensor are provided in the first base and the second base, and the switching mechanism and the backup edge-finding sensor correspond to the positions of the first edge-finding sensor and the second edge-finding sensor. The first edge-finding sensor and the second edge-finding sensor are controlled to rotate 180° through the switching mechanism to switch and enable the backup edge-finding sensor.

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