Wafer drying apparatus and method of wafer cleaning and drying

Abstract

This application relates to a wafer drying apparatus and a method for cleaning and drying wafers. The wafer drying apparatus includes: a tank with a receiving cavity; a tank cover that fits onto the tank; a wafer cassette lifting mechanism disposed in the receiving cavity for supporting and lifting the wafer cassette; a top fixing mechanism including: a wafer separator blade slidably disposed on the tank cover for abutting and limiting the wafers in the wafer cassette from above; a first driver connected to the wafer separator blade for driving the wafer separator blade to move up and down; and a bottom fixing mechanism disposed in the receiving cavity for supporting the wafers after the wafer cassette descends. In this wafer drying apparatus, the wafer separator blade abuts and fixes the wafers from above through point contact, avoiding adsorption between adjacent wafers due to surface tension generated by the IPA liquid film during the drying process, thus improving the drying and cleaning effect and reducing the risk of fragmentation.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing equipment technology, specifically to a wafer drying apparatus and a method for cleaning and drying wafers. Background Technology

[0002] In semiconductor tank cleaning processes, the equipment is typically required to operate in a dry-in, dry-out manner. To ensure effective removal of residual moisture from the wafer surface and control the cleanliness of the wafer surface, IPA (isopropyl alcohol) drying is usually used to dry the wafers in wafer fabrication processes larger than 6 inches.

[0003] The traditional IPA drying method is as follows: IPA vapor is first sprayed out from the top IPA jet pipe to form an IPA liquid film on the water surface inside the IPA drying tank assembly; then, through the relative movement between the wafer and the IPA liquid film, the surface tension difference between the IPA liquid film and the wafer surface is used to carry water and foreign matter from the wafer surface into the IPA liquid film, thereby achieving wafer drying.

[0004] Traditional IPA drying methods have some shortcomings when applied to 12-inch ultra-thin wafer products, especially for wafers with a thickness of less than 100μm. Summary of the Invention

[0005] In view of the above problems, this application provides a wafer drying apparatus and a wafer cleaning and drying method, which facilitates the cleaning and drying of thin wafers.

[0006] In a first aspect, this application provides a wafer drying apparatus, comprising: The tank has a receiving cavity; A cover that fits over the groove body; A wafer cassette lifting mechanism is disposed in the receiving cavity and is used to support the wafer cassette and drive the wafer cassette to move up and down; Top fixing mechanism, including: A wafer separator blade is slidably disposed on the slot cover and is used to abut and limit the wafers in the wafer cassette from above; A first driver, connected to the wafer separator, is used to drive the wafer separator to move up and down; A bottom fixing mechanism is disposed in the receiving cavity to support the wafer after the wafer cassette is lowered.

[0007] According to some embodiments of this application, the wafer drying apparatus further includes: An IPA nozzle extends into the receiving cavity for injecting IPA vapor into the receiving cavity; A nitrogen nozzle extends into the receiving cavity for injecting nitrogen into the receiving cavity; The inlet pipe and the outlet pipe are respectively connected to the receiving cavity.

[0008] According to some embodiments of this application, the nitrogen nozzle includes: The first nitrogen nozzle is provided with multiple first nitrogen nozzles. After the wafer cassette moves to the wafer cassette lifting mechanism, the jet direction of the first nitrogen nozzles is towards the wafer. The second nitrogen nozzle is provided with multiple second nitrogen nozzles. After the wafer cassette moves to the wafer cassette lifting mechanism, the jet direction of the second nitrogen nozzles is toward the gap between adjacent wafers.

[0009] According to some embodiments of this application, the wafer drying apparatus further includes: An attitude detector is used to detect the attitude of the wafer.

[0010] According to some embodiments of this application, the IPA nozzle includes a top-mounted IPA nozzle, which is disposed on the bottom surface of the tank cover; The nitrogen nozzle includes a top-mounted nitrogen nozzle, which is disposed on the bottom surface of the tank cover.

[0011] According to some embodiments of this application, the IPA nozzle further includes a side-mounted IPA nozzle, which is disposed on the side wall of the tank. The nitrogen nozzle also includes a side-mounted nitrogen nozzle, which is disposed on the side wall of the tank.

[0012] According to some embodiments of this application, the wafer separator includes: Separator substrate; Multiple V-shaped teeth are sequentially arranged on the separator blade base, and a limiting groove is formed between adjacent V-shaped teeth for clamping the wafer.

[0013] According to some embodiments of this application, the V-shaped teeth are provided with air jet ports for spraying air into the limiting groove.

[0014] According to some embodiments of this application, the thickness of the wafer is less than or equal to 50 μm.

[0015] Secondly, this application provides a method for cleaning and drying a wafer using the wafer drying apparatus described above, comprising: The wafer cassette containing the wafer is placed on the wafer cassette lifting mechanism. The wafer cassette lifting mechanism is controlled to lower the wafer cassette so that the wafer falls into the bottom fixing mechanism and the slot cover is closed. The wafer separator is controlled to descend and come into contact with the wafer, thereby limiting the top of the wafer; Water is injected into the cavity; The wafer cassette lifting mechanism is controlled to lower the wafer cassette so that the wafer is detached from the wafer cassette; IPA vapor is introduced into the containment cavity to form an IPA liquid film on the water surface, and the water in the containment cavity is discharged, causing the IPA liquid film to descend with the water surface; Hot nitrogen gas is introduced into the cavity to dry the wafer; The wafer cassette lifting mechanism is controlled to lift the wafer cassette, so that the wafer enters the wafer cassette, and the wafer separator is controlled to reset.

[0016] According to some embodiments of this application, the method further includes: Before the wafer separator blade descends, nitrogen gas is injected from the nitrogen nozzle into the gap between adjacent wafers to correct any skewed wafers.

[0017] According to some embodiments of this application, the method further includes: Hot nitrogen gas is ejected from the jet nozzle of the wafer separator to dry the limiting groove of the wafer separator.

[0018] According to some embodiments of this application, draining the water from the receiving cavity includes: The water level drops at a first velocity before it reaches the height of the wafer. As the water surface passes through the height region of the wafer, the water surface descends at a second velocity; After the water surface detaches from the wafer, the water surface descends at a third speed, wherein both the first speed and the third speed are greater than the second speed.

[0019] The wafer drying apparatus of this application employs a wafer fixing and wafer cassette descent method during the drying process. Slow dehydration of the wafer and IPA liquid film is achieved by the IPA liquid film slowly draining down with the pure water in the tank. A wafer separator blade provides point-contact fixing to the wafer from above, separating adjacent wafers. This prevents adsorption between adjacent wafers due to surface tension generated by the IPA liquid film during drying, improving drying and cleaning effects and reducing the risk of fragmentation. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without exceeding the scope of protection claimed by this application.

[0021] Figure 1This is a schematic diagram of a wafer drying apparatus according to an embodiment of this application; Figure 2 This is a schematic diagram of the interior of the tank in an embodiment of this application; Figure 3 This is a schematic diagram of the top fixing mechanism in an embodiment of this application; Figure 4 This is a schematic diagram of the wafer separator blade descending according to an embodiment of this application; Figure 5 This is a schematic diagram of the wafer cell descending according to an embodiment of this application; Figure 6 This is a schematic diagram of the IPA nozzle and nitrogen nozzle according to an embodiment of this application; Figure 7 This is a schematic diagram of the first nitrogen nozzle and the second nitrogen nozzle in the embodiments of this application; Figure 8 This is a schematic diagram of the top-mounted nozzle and the side-mounted nozzle in the embodiments of this application; Figure 9 This is a schematic diagram of a wafer separator according to an embodiment of this application; Figure 10 This is a schematic diagram of the jet nozzle in an embodiment of this application; Figure 11 This is a flowchart of the wafer cleaning and drying method according to an embodiment of this application.

[0022] Among them, 100-wafer drying equipment; 1-Tank body, 11-Receiving cavity; 2-Slot cover; 3-Wafer box lifting mechanism, 31-Support frame, 32-Drive mechanism; 4-Top fixing mechanism, 41-Wafer separator, 411-Separator base, 412-V-tooth, 413-Limiting groove, 414-Air jet, 42-First driver; 5- Bottom fixing mechanism, 51- Comb-shaped support structure; 6-IPA nozzle, 6a-top IPA nozzle, 6b-side IPA nozzle; 7-Nitrogen nozzle, 71-First nitrogen nozzle, 711-First nitrogen nozzle, 72-Second nitrogen nozzle, 721-Second nitrogen nozzle, 7a-Top-mounted nitrogen nozzle, 7b-Side-mounted nitrogen nozzle; 8-Inlet pipe; 9-Drain pipe; 10 - wafer, 20 - wafer box. Detailed Implementation

[0023] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0024] Traditional IPA drying equipment uses a wafer cassette to arrange multiple wafers at intervals within the drying device. Then, through the relative movement of the wafers and the IPA liquid film, the surface tension difference between the IPA liquid film and the wafer surface is utilized to carry water and foreign matter from the wafer surface into the IPA liquid film, thereby achieving wafer drying.

[0025] Traditional IPA drying methods have the following drawbacks when applied to 12-inch ultrathin wafer products: In the traditional IPA drying process, no fixed structure is set on the top of the wafer. Adjacent wafers are prone to mutual adsorption due to the surface tension of the IPA liquid film, which affects the drying and cleaning effect of the wafer, resulting in residues on the wafer surface and poor drying.

[0026] To fix the top of the wafer and prevent adjacent wafers from adhering to each other, an existing solution involves installing a rotatable top blade on the inner wall of the drying tank. Once the top blade rotates to a position above the wafer, it abuts and secures the wafer. However, this rotatable top blade, located inside the drying tank, occupies a significant amount of internal space. Furthermore, the top blade requires a considerable stroke to rotate above the wafer, resulting in a lengthy operation and increased processing time, which is detrimental to improving drying efficiency.

[0027] Furthermore, for 12-inch ultrathin wafers with large area and thin thickness, the wafer itself lacks rigidity. During the process of moving the wafer to be dried into the drying equipment, adjacent thin wafers may adhere to each other due to electrostatic attraction, making it difficult to insert the subsequent structure for separating and fixing the top of the wafer between adjacent wafers. This makes it impossible to separate and fix the top of the wafer, affecting the reliability of the drying process.

[0028] like Figure 1 As shown, an embodiment of this application provides a wafer drying apparatus 100, which includes: a tank body 1, a tank cover 2, a wafer box lifting mechanism 3, a top fixing mechanism 4, and a bottom fixing mechanism 5.

[0029] The tank 1 has a top-opening cavity 11 for holding pure water, IPA liquid film, and wafers 10 and wafer cassettes 20 to be dried. The tank cover 2 is fitted onto the tank 1 and can close the top opening of the cavity 11.

[0030] like Figure 2As shown, the wafer cassette lifting mechanism 3 is disposed in the receiving cavity 11, and is used to support the wafer cassette 20 and drive the wafer cassette 20 to move up and down. Exemplarily, the wafer cassette lifting mechanism 3 includes a support frame 31 and a drive mechanism 32. The drive mechanism 32 is disposed on the inner wall of the receiving cavity 11, and the support frame 31 is connected to the drive mechanism 32. The drive mechanism 32 can drive the support frame 31 to move up and down. An existing drive mechanism can be used for the drive mechanism 32.

[0031] like Figure 3 As shown, the top fixing mechanism 4 includes a wafer separator 41 and a first driver 42. The wafer separator 41 is slidably disposed on the slot cover 2 and is used to abut and limit the wafer 10 in the wafer box 20 from above. The first driver 42 is connected to the wafer separator 41 and is used to drive the wafer separator 41 to move up and down. The first driver 42 is disposed on the slot cover 2 and can be a linear drive element such as a cylinder, hydraulic cylinder, or motor screw assembly.

[0032] A bottom fixing mechanism 5 is disposed in the receiving cavity 11 to support the wafer 10 after the wafer cassette 20 descends. In this embodiment, the bottom fixing mechanism 5 is fixedly disposed at the bottom of the tank 1, and the bottom fixing mechanism 5 includes a comb-shaped support structure 51 corresponding to the number of wafers 10. The bottom fixing mechanism 5 is located inside the support frame 31 of the wafer cassette lifting mechanism 3.

[0033] The working process of the wafer drying apparatus 100 includes: After the robotic arm places the wafer cassette 20 containing the wafer 10 onto the wafer cassette lifting mechanism 3, the wafer cassette lifting mechanism 3 drives the wafer cassette 20 to descend, causing the wafer 10 to fall into the bottom fixing mechanism 5. like Figure 4 As shown, when the slot cover 2 is closed, the first driver 42 drives the wafer separator 41 to descend, abut against the wafer 10 from above and limit the top of the wafer 10, and inject water into the receiving cavity 11. like Figure 5 As shown, the wafer cassette lifting mechanism 3 drives the wafer cassette 20 to continue to descend, causing the wafer 10 to detach from the wafer cassette 20; at this time, the wafer 10 is fixed by the wafer separator 41 and the bottom fixing mechanism 5. IPA dehydration: The IPA liquid film descends with the water level in the containment cavity and moves relative to the fixed wafer 10. The surface tension difference is used to carry water and foreign matter from the surface of the wafer 10 into the IPA liquid film, thus achieving slow pull dehydration and drying of the wafer 10.

[0034] Throughout the drying process, wafer 10 remains fixed, and separation and dehydration are achieved by the descent of wafer box 20 and the drop in liquid level, thus avoiding the risks of fragmentation and adsorption caused by the lifting and moving of wafer 10 in traditional solutions.

[0035] In existing rotary top knife grooves, the rotating arm, hinge support, and drive mechanism are all arranged in the lateral space of the receiving cavity, directly encroaching on the wafer processing area. In this embodiment, the wafer separator 41 slides up and down against the wafer 10 from above, occupying less internal space within the groove. During contact with the wafer, the wafer separator 41 makes a short linear movement in the vertical direction, resulting in a small relative sliding distance with the top of the wafer. The rigid wafer separator 41 has a small frictional stroke between itself and the brittle wafer edge, reducing the probability of edge chipping and microcracks in the ultra-thin wafer.

[0036] Existing rotary top cutters, in order to avoid the wafer cassette's loading path, must initially retract completely into the tank sidewall, with their rotational stroke typically covering 1 / 2 to 2 / 3 of the wafer radius. In this embodiment, the wafer separator 41 is positioned on the tank cover 2, and its initial position is already above the top of the wafer 10, requiring only a short linear motion in the vertical direction. The response speed and positioning accuracy of linear motion are significantly better than rotary motion, compressing the top cutter's action time from several seconds to sub-seconds, directly shortening the single-batch process cycle time and increasing equipment throughput.

[0037] Due to the constraint of rotational motion, the rotating die experiences tangential slippage at the moment of contact with the wafer. In this embodiment, the wafer separator 41 descends vertically, eliminating tangential slippage and leaving only normal clamping force, which helps reduce edge microcracks caused by contact.

[0038] The existing rotary top cutter and its drive mechanism are located deep in the side wall of the tank. Routine maintenance, such as replacing seals and calibrating the zero position, requires operators to enter the receiving cavity or disassemble the side plate, resulting in a large maintenance window and long downtime. In this embodiment, the top fixing mechanism 4 is integrated into the tank cover 2. After the tank cover 2 is opened, the top fixing mechanism 4 is fully exposed to the operator's view, which can realize "open the cover and repair" and reduce maintenance costs.

[0039] like Figure 2 and Figure 6 As shown, in some embodiments, the wafer drying apparatus 100 further includes an IPA nozzle 6, a nitrogen nozzle 7, a liquid inlet pipe 8, and a liquid outlet pipe 9. The IPA nozzle 6 extends into the receiving cavity 11 and is used to spray IPA vapor into the receiving cavity 11 to form an IPA liquid film on the water surface after water injection. The nitrogen nozzle 7 extends into the receiving cavity 11 and is used to spray nitrogen gas into the receiving cavity 11 for drying the wafer 10, wafer cassette 20, and the entire receiving cavity after dehydration. The liquid inlet pipe 8 and the liquid outlet pipe 9 are respectively connected to the receiving cavity 11. The liquid inlet pipe 8 is used to inject pure water into the receiving cavity 11, and the liquid outlet pipe 9 is used to drain the water from the receiving cavity. In this embodiment, the liquid outlet pipe 9 is located at the bottom of the tank 1, and its drainage speed is adjustable to precisely control the rate of water level descent during the dehydration stage.

[0040] like Figure 7 As shown, in some embodiments, the nitrogen nozzle 7 includes a first nitrogen nozzle 71 and a second nitrogen nozzle 72. The first nitrogen nozzle 71 is provided with a plurality of first nitrogen nozzles 711. After the wafer cassette 20 moves to the wafer cassette lifting mechanism 3, the jet direction of the first nitrogen nozzles 711 is towards the wafer. The second nitrogen nozzle 72 is provided with a plurality of second nitrogen nozzles 721. After the wafer cassette 20 moves to the wafer cassette lifting mechanism 3, the jet direction of the second nitrogen nozzles 721 is towards the gap between adjacent wafers 10.

[0041] Before the wafer separator 41 descends, nitrogen gas is injected into the gap between adjacent wafers 10 by the second nitrogen nozzle 72 to correct the skewed wafers and prevent the wafer separator 41 from crushing the skewed wafers.

[0042] Optionally, the second nitrogen nozzle 72 sprays nitrogen into the gap between adjacent wafers 10 in an intermittent purging manner, that is, it sprays nitrogen intermittently according to a preset period, for example, the purging time is 0.5s, the interval time is 0.5s, and the total purging time is 2.5s (that is, nitrogen is purged three times, with an interval of 0.5s between each time). Intermittent purging can create pulsed airflow disturbance between adjacent wafers 10, which facilitates the separation between adjacent wafers 10; at the same time, it can avoid the formation of a continuous low-pressure area covering most of the crystal surface of the wafer in the narrow gap between adjacent wafers 10 by continuous airflow, which prevents the crystal surfaces of adjacent wafers 10 from sticking together under the action of pressure difference and making it difficult to separate. This is beneficial to ensuring the correction effect before the wafer separator blade 41 descends.

[0043] In some embodiments, at least a portion of the second nitrogen nozzle 72 is disposed on the sidewall of the tank 1, and the jet direction of the second nitrogen nozzle is obliquely upward, toward the highest point of the gap between adjacent wafers 10. Since thin wafers are prone to sticking together on top due to electrostatic forces during handling, setting the second nitrogen nozzle to blow obliquely upward from the lower side toward the highest point of the gap allows the nitrogen gas flow to directly impact the sticking area on the top of the wafers 10, using the dynamic pressure of the airflow to quickly separate the sticking wafers 10. Compared to horizontal blowing, the obliquely upward airflow can better overcome the sticking force generated by surface tension or electrostatic adsorption on the top of the wafers 10, especially suitable for situations where the top of the wafers 10 has already significantly stuck together, thereby effectively reducing the risk of interference before the wafer separator 41 is inserted. Preferably, the second nitrogen nozzle 72 also uses an intermittent blowing method to spray nitrogen into the gap between adjacent wafers 10.

[0044] In some embodiments, at least a second nitrogen nozzle 72 is disposed on the sidewall of the tank 1, and the jet direction of the second nitrogen nozzle is obliquely upward, toward the middle of the gap between the wafers 10, so that the purging airflow passes through the middle of the wafers before blowing toward the top of the wafers. Meanwhile, the obliquely upward airflow is preferably a continuous airflow, for example, with a purging time of 1.5 seconds. This is because for a 12-inch wafer, the aspect ratio is relatively large, making it prone to local elastic deformation under external force. The gap between adjacent wafers 10 in the wafer cassette is only a few millimeters. When the nitrogen airflow purifies the gap between the middle parts of the wafers 10, the middle part is more likely to undergo elastic deformation due to the pressure difference generated by the Bernoulli effect, thus creating a tendency for them to move closer together, which in turn promotes the separation of the tops of the wafers 10. Therefore, the effect of intermittent airflow can be achieved in a shorter time using a continuous airflow.

[0045] When drying wafer 10, the first nitrogen nozzle 71 and the second nitrogen nozzle 72 spray gas simultaneously to facilitate the drying of wafer 10.

[0046] In some embodiments, the wafer drying apparatus 100 further includes a posture detector for detecting the posture of the wafer 10. The posture detector may be a photoelectric sensor, laser sensor, or vision detection element disposed on the slot cover 2, for detecting whether the wafer 10 has a posture deviation. If the posture detector detects a deviated wafer, it controls the second nitrogen nozzle 72 to spray gas into the gap between adjacent wafers 10 to correct the deviated wafer. If there are still deviated wafers after the second nitrogen nozzle 72 sprays gas, the wafer drying apparatus 100 may issue an alarm and stop the process.

[0047] like Figure 8 As shown, in some embodiments, the IPA nozzle 6 includes a top-mounted IPA nozzle 6a, which is disposed on the bottom surface of the tank cover 2. The nitrogen nozzle 7 includes a top-mounted nitrogen nozzle 7a, which is disposed on the bottom surface of the tank cover 2. By placing the nozzles on the bottom surface of the tank cover 2, the distance between the nozzle and the wafer 10 can be shortened, allowing the IPA vapor to reach the water surface more quickly and the nitrogen gas to be blown more directly onto the wafer 10, thereby improving film quality and drying efficiency. Simultaneously, since this embodiment eliminates the need for complex wafer guiding structures such as wafer guide plates on the tank cover 2, the structure of the tank cover 2 is simplified, reducing dead corners and gaps inside the chamber and lowering the risk of particle accumulation.

[0048] In some embodiments, the IPA nozzle 6 further includes a side-mounted IPA nozzle 6b, which is disposed on the side wall of the tank 1. The nitrogen nozzle 7 further includes a side-mounted nitrogen nozzle 7b, which is disposed on the side wall of the tank 1. The side-mounted nozzles, in conjunction with the top-mounted nozzle, can make the IPA vapor more evenly distributed within the containment cavity. Those skilled in the art will understand that the top-mounted nozzle and the side-mounted nozzle can be selected individually or simultaneously, depending on the tank size and process requirements.

[0049] like Figure 9 As shown, in some embodiments, the wafer separator 41 includes a separator base 411 and a plurality of V-shaped teeth 412. The plurality of V-shaped teeth 412 are sequentially arranged on the separator base 411 along the arrangement direction of the wafers 10, and a limiting groove 413 is formed between adjacent V-shaped teeth 412 for clamping the wafers 10. When the first driver 42 drives the wafer separator 41 to descend, the top of each wafer 10 enters the corresponding limiting groove 413, and the V-shaped teeth 412 insert between adjacent wafers 10 to separate them, forming point contact or near-point contact with the wafers 10, thereby limiting the top of the wafers 10. During the slow-pull dehydration process, the wafers 10 are fixed by the wafer separator 41 and the bottom fixing mechanism 5, effectively preventing adjacent wafers 10 from adsorbing each other due to the surface tension of the IPA liquid film.

[0050] like Figure 10 As shown, in some embodiments, the V-shaped teeth 412 are provided with jet nozzles 414 for jetting gas into the limiting groove 413. The injected gas can be nitrogen. After dehydration, hot nitrogen can be sprayed into the limiting groove 413 through the jet nozzles 414 to dry the limiting groove 413 and the top edge of the wafer 10 in contact with it, so as to avoid the presence of residual liquid in the limiting groove 413.

[0051] Optionally, during the descent of the wafer separator 41, gas can be continuously or intermittently ejected from the jet nozzle 414, forming a gas film between the V-shaped teeth 412 and the wafer 10. This gas film acts as a gas lubrication layer, reducing friction between the wafer 10 and the tooth surfaces of the V-shaped teeth 412 as the top of the wafer 10 enters the limiting groove 413, thereby reducing damage to the wafer 10.

[0052] The gas film can be maintained relatively stably during the vertical descent normal motion. If the wafer separator uses a rotating motion, the tangential velocity will destroy the integrity of the gas film, resulting in uneven gas film thickness or even rupture, and loss of lubrication and friction reduction effect.

[0053] In some embodiments, the wafer drying apparatus 100 is suitable for wafers with a thickness of 50 μm or less. The thinner the wafer, the worse its rigidity, and the more prominent the problems of adsorption and fragmentation between adjacent wafers in traditional processes become. Using the wafer drying apparatus 100 of this embodiment, ultra-thin wafers 10 with a thickness of 50 μm or less are cleaned and dried, improving the safety of the wafer.

[0054] like Figure 11 As shown, an embodiment of this application provides a method for cleaning and drying a wafer using the wafer drying apparatus described above, comprising: S1. Place the wafer cassette 20 containing the wafer 10 onto the wafer cassette lifting mechanism 3, control the wafer cassette lifting mechanism 3 to drive the wafer cassette 20 down, so that the wafer 10 falls into the bottom fixing mechanism 5, and close the slot cover 2.

[0055] Specifically, a robotic arm can transport and place the wafer cassette 20 containing the wafer 10 onto the wafer cassette lifting mechanism 3. After the wafer cassette 20 is lowered by the wafer cassette lifting mechanism 3, the wafer 10 is supported by the bottom fixing mechanism 5. After the tank cover 2 is closed, the tank cover 2 and the tank body 1 form a relatively sealed processing chamber.

[0056] S2. Control the wafer separator blade 41 to descend so as to come into contact with the wafer 10 and limit the top of the wafer 10.

[0057] Specifically, the first driver 42 drives the wafer separator 41 to descend, and the top of each wafer 10 enters the corresponding limiting groove 413. The V-shaped teeth 412 are inserted between adjacent wafers 10 to separate the adjacent wafers 10 and to make point contact and fix the wafers 10.

[0058] S3. Pour water into the receiving cavity.

[0059] Specifically, pure water is injected into the receiving cavity 11 through the liquid inlet pipe 8 until the water surface covers the wafer cassette and the wafer 10, so as to wet the surface of the wafer 10 and prepare for subsequent IPA dehydration.

[0060] S4. Control the wafer box lifting mechanism 3 to drive the wafer box 20 down so that the wafer 10 is separated from the wafer box 20.

[0061] Specifically, the wafer cassette lifting mechanism 3 drives the wafer cassette 20 to continue descending to a low position, completely disengaging the periphery of the wafer cassette 20 from its slot, and the wafer 10 is completely secured by the bottom fixing mechanism 5 and the wafer separator 41. Therefore, the wafer cassette 20 no longer exerts any constraint on the wafer 10 during the subsequent dehydration process.

[0062] S5. IPA vapor is introduced into the containment chamber through the IPA nozzle 6, forming an IPA liquid film on the water surface, and the water in the containment chamber is discharged, causing the IPA liquid film to descend with the water surface.

[0063] Specifically, the top-mounted IPA nozzle 6a and / or the side-mounted IPA nozzle 6b inject IPA vapor into the receiving cavity 11. The IPA vapor condenses on the water surface to form an IPA liquid film. Subsequently, the drain pipe 9 drains the water from the receiving cavity, and the water surface and the IPA liquid film covering it slowly descend. The fixed wafer 10 is gradually exposed relative to the IPA liquid film. Utilizing the surface tension difference between the IPA liquid film and the surface of the wafer 10, water and foreign matter on the surface of the wafer 10 are carried into the IPA liquid film, achieving slow dehydration of the wafer 10. Since the wafer 10 remains fixed throughout the process, there is no wafer lifting out of the water surface, thus avoiding interference with the guide components caused by wafer movement and warping and adsorption problems at the moment of water exit.

[0064] S6. Hot nitrogen gas is introduced into the containment cavity through the nitrogen nozzle 7 to dry the wafer 10.

[0065] Specifically, after dehydration, hot nitrogen gas is injected into the containment cavity through the top nitrogen nozzle 7a and / or the side nitrogen nozzle 7b to dry the wafer 10, the wafer box 20 and the entire chamber, so that the surface of the wafer 10 is completely dry.

[0066] S7. Control the wafer cassette lifting mechanism 3 to drive the wafer cassette 20 to rise, so that the wafer cassette 20 rises until the wafer 10 enters the wafer cassette 20, and control the wafer separator blade 41 to reset.

[0067] Specifically, after drying is completed, the wafer cassette lifting mechanism 3 drives the wafer cassette 20 to a high position, so that each wafer 10 falls back into the corresponding slot of the wafer cassette 20; then the first driver 42 drives the wafer separator 41 to rise and reset, and the wafer separator 41 separates from the wafer 10.

[0068] Open the tank cover 2, and the wafer box lifting mechanism 3 will drive the wafer box 20 to rise. The robotic arm will then take out the wafer box 20 containing the dried wafer 10, completing one drying cycle.

[0069] In some embodiments, the method further includes: injecting nitrogen gas from a nitrogen nozzle 7 into the gap between adjacent wafers 10 before the wafer separator 41 descends, in order to correct the skewed wafers.

[0070] Specifically, the thin wafer may be tilted during handling and placement. Before the wafer separator 41 descends, nitrogen gas is sprayed into the gap between adjacent wafers using the second nitrogen nozzle 72 to push the tilted wafer back to its normal position. This can prevent the wafer from being crushed by the wafer separator 41 and breaking apart when it is tilted, and it also makes it easier for the V-shaped teeth 412 of the wafer separator 41 to be accurately inserted between adjacent wafers.

[0071] Optionally, the attitude detector first detects the attitude of wafer 10, and when wafer 10 is detected to be skewed, the above-mentioned correction jet is then performed.

[0072] In some embodiments, the method further includes: spraying hot nitrogen gas from the jet nozzle 414 of the wafer separator 41 to dry the limiting groove 413 of the wafer separator 41. This step can be performed simultaneously with the overall hot nitrogen drying stage in step S6, thereby preventing residual liquid in the limiting groove 413 from dripping or adhering to the surface of the wafer 10 when the wafer separator 41 is lifted, and ensuring the drying effect of the top edge of the wafer 10.

[0073] In some embodiments, draining the water from the receiving cavity in step S5 includes: The water level drops at the first velocity before it reaches the height of wafer 10; As the water surface passes through the height region of wafer 10, the water surface descends at a second speed; After the water surface detaches from wafer 10, the water surface descends at a third speed; where both the first and third speeds are greater than the second speed.

[0074] The stage where the water surface passes through the height region of wafer 10 is a crucial stage of slow-pull dehydration. A lower second speed (i.e., slow discharge) ensures that the IPA liquid film smoothly sweeps across the surface of wafer 10, allowing the surface tension difference to stably exert its dehydration effect. This avoids liquid surface fluctuations disturbing wafer 10, which could lead to mutual adsorption between adjacent wafers or uneven dehydration. However, in the stages before the water surface reaches wafer 10 or after it has completely detached from wafer 10, a faster first and third speed is used to lower the water surface, shortening the process cycle and improving drying efficiency.

[0075] For example, the wafer drying apparatus 100 includes a level gauge to detect the liquid level in the receiving cavity. A first speed is 1.5-4 mm / s, a second speed is 0.2-1.0 mm / s, and a third speed is 1.5-4 mm / s.

[0076] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the technical solutions and core ideas of this application. Therefore, any changes or modifications made by those skilled in the art based on the ideas of this application, and on the specific implementation methods and application scope of this application, are all within the scope of protection of this application. In summary, the content of this specification should not be construed as a limitation of this application.

Claims

1. A wafer drying apparatus, characterized in that, include: The tank has a receiving cavity; A cover that fits over the groove body; A wafer cassette lifting mechanism is disposed in the receiving cavity and is used to support the wafer cassette and drive the wafer cassette to move up and down; Top fixing mechanism, including: A wafer separator blade is slidably disposed on the slot cover and is used to abut and limit the wafers in the wafer cassette from above; A first driver, connected to the wafer separator, is used to drive the wafer separator to move up and down; A bottom fixing mechanism is disposed in the receiving cavity to support the wafer after the wafer cassette is lowered; An IPA nozzle extends into the receiving cavity for injecting IPA vapor into the receiving cavity; A nitrogen nozzle extends into the receiving cavity for injecting nitrogen into the receiving cavity; The inlet pipe and the outlet pipe are respectively connected to the receiving cavity.

2. The wafer drying apparatus according to claim 1, characterized in that, The nitrogen nozzle includes: The first nitrogen nozzle is provided with multiple first nitrogen nozzles. After the wafer cassette moves to the wafer cassette lifting mechanism, the jet direction of the first nitrogen nozzles is towards the wafer. The second nitrogen nozzle is provided with multiple second nitrogen nozzles. After the wafer cassette moves to the wafer cassette lifting mechanism, the jet direction of the second nitrogen nozzles is toward the gap between adjacent wafers.

3. The wafer drying apparatus according to claim 2, characterized in that, Also includes: An attitude detector is used to detect the attitude of the wafer.

4. The wafer drying apparatus according to claim 1, characterized in that, The IPA nozzle includes a top-mounted IPA nozzle, which is disposed on the bottom surface of the tank cover; The nitrogen nozzle includes a top-mounted nitrogen nozzle, which is disposed on the bottom surface of the tank cover.

5. The wafer drying apparatus according to claim 4, characterized in that, The IPA nozzle also includes a side-mounted IPA nozzle, which is disposed on the side wall of the tank. The nitrogen nozzle also includes a side-mounted nitrogen nozzle, which is disposed on the side wall of the tank.

6. The wafer drying apparatus according to claim 1, characterized in that, The wafer separator includes: Separator substrate; Multiple V-shaped teeth are sequentially arranged on the separator blade base, and a limiting groove is formed between adjacent V-shaped teeth for clamping the wafer.

7. The wafer drying apparatus according to claim 6, characterized in that, The V-shaped teeth are provided with air jets for injecting air into the limiting groove.

8. The wafer drying apparatus according to claim 1, characterized in that, The thickness of the wafer is less than or equal to 50 μm.

9. A method for cleaning and drying wafers using the wafer drying apparatus according to any one of claims 1 to 8, characterized in that, include: The wafer cassette containing the wafer is placed on the wafer cassette lifting mechanism. The wafer cassette lifting mechanism is controlled to lower the wafer cassette so that the wafer falls into the bottom fixing mechanism and the slot cover is closed. The wafer separator is controlled to descend and come into contact with the wafer, thereby limiting the top of the wafer; Water is injected into the cavity; The wafer cassette lifting mechanism is controlled to lower the wafer cassette so that the wafer is detached from the wafer cassette; IPA vapor is introduced into the containment cavity to form an IPA liquid film on the water surface, and the water in the containment cavity is discharged, causing the IPA liquid film to descend with the water surface; Hot nitrogen gas is introduced into the cavity to dry the wafer; The wafer cassette lifting mechanism is controlled to lift the wafer cassette, so that the wafer cassette is raised to the position of carrying the wafer, and the wafer separator is controlled to reset.

10. The method according to claim 9, characterized in that, Also includes: Before the wafer separator blade descends, nitrogen gas is injected through a nitrogen nozzle into the gap between adjacent wafers to correct any skewed wafers.

11. The method according to claim 9, characterized in that, Also includes: Hot nitrogen gas is ejected from the jet nozzle of the wafer separator to dry the limiting groove of the wafer separator.

12. The method according to claim 9, characterized in that, The step of draining the water from the receiving cavity includes: The water level drops at a first velocity before it reaches the height of the wafer. As the water surface passes through the height region of the wafer, the water surface descends at a second velocity; After the water surface detaches from the wafer, the water surface descends at a third velocity, wherein both the first velocity and the third velocity are greater than the second velocity.

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