Wafer fork and overlay detection apparatus with unequal length prong arms

Abstract

The application provides a wafer fork with unequal-length fork arms and a overlay amount detection device, and belongs to the field of semiconductor wafer devices. The wafer fork comprises a fork base and a fork head, the fork head comprises two unequal-length fork arms, and an air disc is arranged on the fork arm. The overlay amount detection device comprises a moving table, a wafer loading disc, a light machine detection module, a feeding and discharging mechanism and a processor, two parallel unequal-length material taking grooves are formed in the wafer loading disc, and the feeding and discharging mechanism adopts the wafer fork. In the application, the two fork arms are arranged in an unequal-length asymmetric structure, which can accurately adapt to the asymmetric material taking grooves with unequal depths on the wafer loading disc, avoids the problems of arm body collision with the groove wall of the loading disc and low alignment efficiency in the taking and placing process of the traditional equal-length fork, improves the wafer transfer rate, and can be widely applied in the field of semiconductor wafer transfer.

Description

Technical Field

[0001] This application belongs to the field of semiconductor wafer transport equipment, specifically relating to a wafer tooth fork with unequal length tooth fork arms and a calibration and detection device. Background Technology

[0002] In semiconductor manufacturing processes, wafer transfer robots are core components connecting various process equipment. The wafer pick-and-place fork, as the direct bearing and placement mechanism at the end of the robot, has a structural design that directly determines the stability and safety of wafer handling. Currently, the industry-standard wafer pick-and-place forks all adopt a symmetrical, equal-length double-arm structure, with both arms being exactly the same length. This design is only suitable for scenarios where equal-length symmetrical pick-and-place slots are provided on the wafer carrier.

[0003] With the rapid iteration of advanced packaging and 3D integration processes, some process trays are being designed with asymmetric, unequal-length pick-up slot structures to optimize spatial layout, increase the number of wafers a single tray can hold, and avoid positioning bosses, detection sensors, and other auxiliary components on the tray, thereby improving alignment speed. Traditional equal-length pick-up forks entering these trays require ensuring that both fork arms are simultaneously aligned with the two tray slots. This process is computationally time-consuming and prone to rigid collisions between one arm and the tray wall. This can lead to wafer misalignment and increased breakage, or even direct damage to the tray and pick-up fork structure, significantly increasing equipment maintenance costs and downtime. Therefore, developing a novel wafer pick-up fork structure suitable for unequal-length pick-up slot scenarios has become a pressing technical challenge in this field. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the present invention aims to provide a wafer tooth fork with unequal length tooth fork arms and a wafer calibration and inspection device, which can solve the above-mentioned problems and improve the compatibility and operational stability of the wafer pick-and-place process. The overall design scheme is as follows.

[0005] A wafer fork with unequal-length fork arms, the wafer fork including a fork base and a fork head, the fork head including two fork arms of unequal length, and a gas disk disposed on the fork arms.

[0006] Furthermore, a head air groove is opened on the bottom surface of the fork head to lead to the two fork arms, and a head sealing plate is installed at the air groove.

[0007] Furthermore, a base air groove and a corresponding base sealing plate are opened at the base of the toothed fork for supplying air to and / or drawing air into the head air groove of the toothed fork.

[0008] Furthermore, a lower air groove and a corresponding lower sealing plate are formed on the bottom surface of the tooth fork base, and an upper air groove and a corresponding upper sealing plate are formed on the top surface of the tooth fork base, wherein the lower air groove and the upper air groove are connected.

[0009] Furthermore, the two fork arms of unequal lengths are arranged in parallel, and the length difference between the two fork arms matches the depth difference of the unequal-length pick-up slots opened on the wafer carrier.

[0010] Furthermore, the toothed fork head has multiple vent holes on its upper surface away from the head sealing plate. These vent holes are connected to the internal head air groove, and each vent hole is fitted with an air plate.

[0011] Furthermore, the center of the air plate is equipped with both an adsorption air hole and an annular air blowing hole, and both the adsorption air hole and the air blowing hole are connected to the corresponding ventilation hole.

[0012] Furthermore, the upper surfaces of both fork arms of the fork head are provided with contour-fitting limiting edges that match the edge curvature of wafers of different sizes.

[0013] Furthermore, a mounting part is provided at the front end of the fork base, and the fork head is connected to the mounting part of the fork base through a fork fixing plate.

[0014] This application also provides a calibration and inspection device, including a motion stage, a wafer carrier, an optomechanical inspection module, a loading and unloading mechanism, and a processor. The wafer carrier has two parallel and unequal length picking slots, and the loading and unloading mechanism adopts the aforementioned wafer tooth fork.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This application sets the two toothed fork arms to an asymmetrical structure of unequal length, which can accurately adapt to the asymmetrical pick-up slots of unequal depth on the wafer carrier, avoiding problems such as collision between the arm body and the carrier slot wall and low alignment efficiency that occur during the pick-up and drop process of traditional toothed forks of equal length, and reducing the wafer fragmentation rate by more than 80%.

[0016] The built-in through-type air groove, combined with the air-blowing adsorption plate, can simultaneously achieve negative pressure adsorption and fixation of the wafer and positive pressure air blowing cleaning after unloading. While ensuring no deviation during wafer transfer, it effectively removes micro-particle impurities from the back of the wafer and the surface of the carrier, reducing the risk of process contamination.

[0017] The entire structure adopts a one-piece ceramic molding structure, combined with a detachable air groove plate, which not only ensures the overall rigidity of the structure, but also facilitates the regular cleaning and maintenance of the internal air groove, greatly extending the overall service life of the toothed fork and reducing the operation and maintenance costs of semiconductor equipment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the wafer tooth fork with unequal length tooth fork arms of the present invention; Figure 2 This is a schematic diagram showing another perspective of the wafer toothed fork; Figure 3 This is an exploded view of a wafer toothed fork. Figure 4 This is a partial structural diagram of a wafer toothed fork. Figure 5 Schematic diagrams of wafer toothed forks with different examples of gas grooves. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] A wafer fork with unequal-length fork arms, the wafer fork including a fork base 1 and a fork head 2, the fork head 2 including two fork arms of unequal length, with a gas disk 4 disposed on the fork arms. The two unequal-length fork arms are a long fork arm 21 and a short fork arm 22.

[0021] A head air groove 23 is opened on the bottom surface of the fork head 2, leading to the two fork arms, and a head sealing plate 5 is installed at the air groove.

[0022] A base air groove and a corresponding base sealing plate are opened at the base 1 of the toothed fork to supply air to and / or draw air into the head air groove 23 of the toothed fork head 2.

[0023] A lower air groove 11 and a corresponding lower sealing plate 6 are provided on the bottom surface of the tooth fork base 1, and an upper air groove 12 and a corresponding upper sealing plate 7 are provided on the top surface of the tooth fork base 1, wherein the lower air groove 11 and the upper air groove 12 are connected.

[0024] A sealing silicone gasket is installed between the mating surfaces of the sealing plate (5 / 6 / 7) and the air groove (23 / 11 / 12) to ensure the overall airtightness of the air passage.

[0025] In a specific example, the head air grooves 23 at the long tooth fork arm 21 and the short tooth fork arm 22 can be connected or independent, and the base air groove at the tooth fork base 1 can be one or two. To enable independent air supply at the two tooth fork arms, the head air grooves 23 at the long tooth fork arm 21 and the short tooth fork arm 22 need to be independently opened and not connected. Of course, it can also be controlled by an air valve.

[0026] Corresponding to the two independent head air slots 23, two sets of base air slots are provided to supply air to the two head air slots 23 respectively. Because the width of the fork base 1 is generally narrower than the overall width of the fork head 2, in the case where a lower base air slot 11 and an upper base air slot 12 are provided, the upper base air slot 12, which is closer to the head air slot 23, is set at an angle to connect the head air slot 23 and the lower base air slot 11. In this case, the lower base air slot 11 is used to connect to an external air source.

[0027] Of course, only one of the air groove 11 under the base and the air groove 12 on the base can be provided, as long as it serves to connect the external air source and the head air groove 23.

[0028] See Figure 5 , Figure 5 a indicates that only one lower air groove 11 is opened on the tooth fork base 1, and the head air groove 23 is set to be a single connected one; Figure 5 b indicates that two lower air grooves 11 are opened on the tooth fork base 1 and two head air grooves 23 are opened on the tooth fork head 2. The two lower air grooves 11 are respectively connected to the corresponding head air grooves 23. Figure 5 c and Figure 5 d indicates that the tooth fork base 1 has two lower air grooves 11 and two upper air grooves 12, and the tooth fork head 2 has two head air grooves 23. The two upper air grooves 12 are respectively connected to the corresponding head air grooves 23.

[0029] The two fork arms of unequal lengths of the fork head 2 are arranged in parallel, and the length difference between the two fork arms matches the depth difference of the unequal-length pick-up slots opened on the wafer carrier.

[0030] Each toothed fork arm includes multiple support segments of varying thicknesses that match the wafer size, gradually increasing in thickness from front to back. Corresponding to each support segment, at least one of the two toothed fork arms is equipped with an air plate 4.

[0031] The toothed fork head 2 has multiple vent holes on its upper surface away from the head sealing plate 5. The vent holes are connected to the internal head air groove 23, and an air plate 4 is embedded in each vent hole.

[0032] The center of the air tray 4 is equipped with both an adsorption vent and an annular air blowing vent, both of which are connected to corresponding ventilation holes. This provides negative pressure adsorption and fixation during the material handling stage, and positive pressure air blowing to clean the back surface of the wafer and the contact surface with the carrier after material unloading.

[0033] Air plate 4 is made of porous polyurethane material. To achieve both air blowing and adsorption functions, corresponding air tubes can be installed in the air groove. Of course, air plate 4 can also be a Bernoulli air plate.

[0034] The upper surfaces of both fork arms of the toothed fork head 2 are provided with contour-fitting limiting edges that match the edge curvature of wafers of different sizes. This design allows for radial limiting of the wafer without contacting the patterned area on the back of the wafer.

[0035] In specific examples, the height of the contour-following limiting edge is set to 1.5mm-2mm, gradually increasing in thickness from front to back. In one example, the edge height is set to 1.8mm, which is just enough to limit the outer edge of the 8-inch wafer and prevent radial slippage of the wafer during high-speed transmission.

[0036] A mounting part is provided at the front end of the fork base 1, and the fork head 2 is connected to the mounting part of the fork base 1 through the fork fixing plate 3.

[0037] Two quick-connect pneumatic connectors are installed on the air path of the base air groove of the tooth fork base 1, which are respectively connected to the external positive pressure air source and the negative pressure generating device to realize the rapid connection and switching of the air path.

[0038] Both the toothed fork base 1 and the toothed fork head 2 are integrally sintered from high-strength alumina ceramic, with the overall surface roughness controlled below Ra0.8. They possess excellent insulation and wear resistance, making them suitable for use in cleanroom environments of Class 100 and above.

[0039] Of course, this application also provides tooth fork structures of different embodiments, as follows, all of which are within the scope of this application.

[0040] Split-type arm variant: The long fork arm 21 and the short fork arm 22 adopt a detachable locking structure to connect with the main body of the fork head 2 or the fork base 1. The arm body of different lengths can be quickly replaced according to the groove depth difference of different carrier plates without replacing the entire fork, which greatly reduces the usage cost of adapting to multiple scenarios.

[0041] Built-in independent air path variant: The long tooth fork arm 21 and the short tooth fork arm 22 are equipped with two completely independent air paths, which correspond to independent negative pressure and positive pressure control circuits respectively. This enables independent timing control of the adsorption and air blowing actions of the two arms, adapting to special carrier disk scenarios with eccentric wafer placement.

[0042] Antistatic coating variant: An additional 10μm thick DLC diamond-like carbon antistatic coating is deposited on the outer surface of the ceramic arms of the long tooth fork arm 21 and the short tooth fork arm 22, with the surface resistance controlled in the range of 10-10Ω, further eliminating the risk of damage to the wafer circuit by electrostatic discharge, and adapting to the high-requirement scenarios of logic chip processes.

[0043] Variant with position detection: Miniature fiber optic sensors are embedded at the front ends of the long tooth fork arm 21 and the short tooth fork arm 22, which can detect in real time whether the wafer is misaligned on the tooth fork. Once the position exceeds the tolerance, the robot arm will be immediately triggered to stop and alarm, so as to avoid the wafer being forcibly entered into the carrier tray and causing a jamming and fragmentation accident.

[0044] Applicable Scenarios: This wafer fork structure with unequal-length fork head arms can be directly adapted to four types of mainstream semiconductor process equipment: ① wafer stage for flip chip bonding machines in advanced packaging; ② wafer annealing furnace carrier boat in 3D NAND memory technology; ③ silicon carbide epitaxial wafer carrier in compound semiconductors; ④ wafer quantity inspection equipment. Addressing the pain points of transmission lag and high breakage rates previously caused by asymmetric pick-up slots in these devices, this structure requires no modification to the original carrier; adaptation is achieved simply by replacing the end forks. The modification cost is low, the implementation cycle is short, and it has extremely high industrial promotion value.

[0045] Specifically, for category ④, this application provides a set of calibration and inspection equipment, including a motion stage, a wafer carrier, an optomechanical inspection module, a loading and unloading mechanism, and a processor. The wafer carrier has two parallel and unequal length picking slots, and the loading and unloading mechanism adopts the aforementioned wafer tooth fork.

[0046] Performance test: A wafer pick-and-place test was conducted for 72 hours on wafer pick-and-place devices with unequal length pick-and-place arms and conventional equal length pick-and-place arms. The test object was a 12-inch carrier with unequal length pick-and-place slots with a 25mm depth difference. The test results are as follows. Test data shows that this structure completely solves the problems of pick-up and drop-off efficiency and alignment efficiency of asymmetric carrier disks, and achieves orders of magnitude performance improvement in core indicators such as positioning accuracy, debris control, and particle management.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wafer toothed fork with unequal-length toothed fork arms, characterized in that: The wafer toothed fork includes a toothed fork base (1) and a toothed fork head (2). The toothed fork head (2) includes two toothed fork arms of unequal lengths, and a gas disk (4) is provided on the toothed fork arms.

2. The wafer toothed fork according to claim 1, characterized in that: A head air groove (23) is made on the bottom surface of the fork head (2) leading to the two fork arms, and a head sealing plate (5) is set at the air groove.

3. The wafer toothed fork according to claim 2, characterized in that: A base air groove and a corresponding base sealing plate are opened at the tooth fork base (1) for supplying air and / or drawing air to the head air groove (23) of the tooth fork head (2).

4. The wafer toothed fork according to claim 3, characterized in that: A lower air groove (11) and a corresponding lower sealing plate (6) are opened on the bottom surface of the tooth fork base (1), and an upper air groove (12) and a corresponding upper sealing plate (7) are opened on the top surface of the tooth fork base (1), wherein the lower air groove (11) and the upper air groove (12) are connected.

5. The wafer toothed fork according to claim 1, characterized in that: The two tooth fork arms of unequal lengths of the tooth fork head (2) are set in parallel, and the length difference between the two tooth fork arms matches the depth difference of the unequal length pick-up slots opened on the wafer carrier.

6. The wafer toothed fork according to claim 2, characterized in that: The toothed fork head (2) has multiple vent holes on its upper surface away from the head sealing plate (5). The vent holes are connected to the internal head air groove (23), and each vent hole is fitted with an air plate (4).

7. The wafer toothed fork according to claim 6, characterized in that: The center of the air plate (4) is provided with both an adsorption air hole and an annular air blowing hole, and both the adsorption air hole and the air blowing hole are connected to the corresponding ventilation hole.

8. The wafer toothed fork according to claim 1, characterized in that: The upper surfaces of the two tooth fork arms of the tooth fork head (2) are provided with contour-fitting limiting edges that match the edge curvature of wafers of different sizes.

9. The wafer toothed fork according to claim 2, characterized in that: The fork base (1) has a mounting part at its front end, and the fork head (2) is connected to the mounting part of the fork base (1) through the fork fixing plate (3).

10. A wafer calibration and inspection device, comprising a motion stage, a wafer carrier, an optomechanical inspection module, a loading and unloading mechanism, and a processor, characterized in that: Two parallel and unequal length pick-up slots are provided on the wafer carrier, and the loading and unloading mechanism adopts the wafer tooth fork described in any one of claims 1-9.

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