Wafer drying method and drying device

Abstract

The invention provides a wafer drying method, and belongs to the technical field of semiconductor manufacturing, and the wafer drying method comprises the following steps: S10, placing a wafer to be cleaned on a rotating chuck, driving the wafer to rotate at a first rotating speed by the rotating chuck, and spraying refrigerated IPA liquid to the center of the wafer at a first flow speed until the IPA liquid is fully distributed on the whole wafer; s20, reducing the flow rate of the IPA liquid to a second flow rate, spraying nitrogen at a preset temperature to the center of the wafer, and blowing the nitrogen and the IPA liquid back and forth between the outer edge of the wafer and the center of the wafer; s30, multiple circles of heating areas are arranged at the bottom of the wafer in the direction from the inner circle to the outer circle, the temperatures of the multiple circles of heating areas are sequentially reduced in the direction away from the axis of the wafer, and the wafer is preliminarily dried; and S40, nitrogen and IPA liquid purging is stopped, the chuck is rotated to drive the wafer to rotate at a second rotating speed, and the second rotating speed is larger than the first rotating speed until the wafer is completely dried.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a wafer drying method and a drying device. Background Art

[0002] In the semiconductor manufacturing process, wafer drying after chemical mechanical polishing (CMP) is one of the key steps. The drying effect of the wafer directly affects the quality and yield of the device. Commonly used drying methods include gas drying, centrifugal drying, and gaseous IPA (isopropyl alcohol) drying, among which: Gas drying uses high-purity gas (such as nitrogen) to blow directly onto the wafer surface through a nozzle, using the airflow to blow the remaining water or cleaning solution away from the wafer surface. This drying method is slow, and the solution on the wafer surface naturally dries and evaporates under the push of the airflow, which easily forms water marks. Centrifugal drying is to spin the wafer at high speed and use centrifugal force to remove the liquid on the surface of the wafer. This drying method relies on high-speed rotation, which can easily cause damage to the wafer or produce tiny defects during the rotation process. The liquid on the edge is prone to form water stains or contamination. Gaseous IPA drying is based on the concentration gradient Marangoni effect, where IPA vapor replaces ultrapure water for drying. Although this method can achieve good drying effects, the IPA vapor process control is complex, and its flammable properties bring safety issues. Summary of the invention

[0003] The embodiments of the present invention provide a wafer drying method and a drying device, aiming to solve the technical problems that the existing gas drying method is slow and prone to produce water marks, the centrifugal drying method is prone to cause wafer defects and form water marks, and the gaseous IPA drying process is complicated and has safety hazards.

[0004] In a first aspect, an embodiment of the present invention provides a wafer drying method, comprising the following steps: S10: placing the wafer to be cleaned on a rotating chuck, the rotating chuck drives the wafer to rotate at a first speed, and the cooled IPA liquid is sprayed toward the center of the wafer at a first flow rate until the entire wafer is covered; S20: reducing the flow rate of the IPA liquid to a second flow rate, spraying nitrogen gas at a preset temperature toward the center of the wafer, and blowing the nitrogen gas and the IPA liquid back and forth between the outer edge of the wafer and the center of the wafer; S30: a plurality of heating zones are arranged at the bottom of the wafer along the direction from the inner circle to the outer circle, and the temperatures of the plurality of heating zones are successively reduced along the direction away from the wafer axis, so that the wafer is preliminarily dried; S40: Turn off the nitrogen and IPA liquid purge, and rotate the chuck to drive the wafer to rotate at a second speed, which is greater than the first speed, until the wafer is completely dry.

[0005] Compared with the prior art, the solution shown in the embodiment of the present application is to heat the bottom of the wafer in different zones so that the IPA liquid film formed on the surface of the wafer can generate a temperature gradient difference along the radial direction of the wafer. Since the surface tension of the IPA liquid varies with the temperature, the IPA liquid film can be orderly separated from the wafer surface by combining the centrifugal force of the low-speed rotation (first speed) and the nitrogen purge, thereby reducing the damage to the microstructure during the drying process, and the nitrogen purges the wafer after heating, thereby increasing the drying speed. The IPA liquid is initially sprayed onto the wafer at a first flow rate to quickly form a liquid film, and then reduced to a second flow rate during the nitrogen purge, which can help the IPA liquid film to be evenly distributed on the wafer surface, and can also be dried quickly during subsequent drying. During the IPA and nitrogen purges and zone heating, the wafer rotates at a first speed, and a lower speed can avoid damage to the wafer surface. Subsequently, the nitrogen and IPA liquid purges are turned off, and the wafer is increased to a second speed, which can be rotated at a high speed to achieve rapid drying of the wafer, and since no purge is performed at this time, surface damage to the wafer can also be avoided.

[0006] In combination with the first aspect, in a possible implementation manner, the difference between the highest temperature and the lowest temperature in the plurality of heating zones is 50°C.

[0007] In combination with the first aspect, in a possible implementation manner, the plurality of heating zones form a plurality of temperature zones from the center to the edge, and each heating zone corresponds to a temperature zone.

[0008] In combination with the first aspect, in a possible implementation, the plurality of heating zones form a plurality of temperature zones from the center to the edge, the plurality of heating zones constitute a temperature zone, and the number of heating zones included in each temperature zone is the same or different.

[0009] In combination with the first aspect, in a possible implementation, the temperature zone is divided into a first temperature zone, a second temperature zone, a third temperature zone, and a fourth temperature zone which are arranged in sequence along a direction away from the axis of the wafer. The first temperature zone is 65°C~80°C, the second temperature zone is 50°C~65°C, the third temperature zone is 35°C~50°C, and the fourth temperature zone is 25°C~35°C.

[0010] In combination with the first aspect, in a possible implementation, the wafer rotates at a third speed in steps S20 and S30, the third speed is less than the first speed, the first speed is less than or equal to 500rpm, the third speed is 300rpm~500rpm, and the second speed is less than 800rpm.

[0011] In combination with the first aspect, in a possible implementation, the first flow rate is 80 ml / min to 120 ml / min, and the second flow rate is 50 ml / min to 80 ml / min.

[0012] In combination with the first aspect, in a possible implementation, the temperature of the IPA liquid after refrigeration is 0°C~25°C, and the preset temperature is 65°C~80°C.

[0013] In a second aspect, an embodiment of the present invention further provides a wafer drying device for implementing the above-mentioned wafer drying method, comprising: Base; A rotating mechanism is arranged on the base, a rotating chuck is arranged on the top of the rotating mechanism, and a through hole is arranged in the middle of the rotating mechanism; A heating mechanism is disposed on the base and passes through the through hole, wherein the heating mechanism has a heating disk located below the rotating chuck, and the heating disk has a plurality of heating zones arranged from the inside to the outside; An operating arm, comprising a fixed arm fixed to the base, and a rotating arm fixed to the top of the fixed arm, the fixed arm extending up and down, the rotating arm extending horizontally, and the rotating arm being used to lift and lower and rotate around the axial direction of the fixed arm; The spray assembly comprises a nitrogen pipeline, a nitrogen nozzle connected to the nitrogen pipeline, an IPA pipeline, and an IPA nozzle connected to the IPA pipeline. The nitrogen nozzle and the IPA nozzle are both fixedly arranged at the free end of the rotating arm. A heating mechanism is arranged on the nitrogen pipeline, and a cooling mechanism is arranged on the IPA pipeline.

[0014] Compared with the prior art, the solution shown in the embodiment of the present application is that a through hole is provided on the rotating mechanism, so that the wafer can be driven to rotate and heated at the same time, thereby facilitating the temperature gradient control on the wafer; a refrigeration mechanism is provided on the IPA pipeline to cool the IPA liquid, and a heating mechanism is provided on the nitrogen pipeline to maintain a constant temperature of the nitrogen, which can be automatically achieved during the spraying process, and the temperature regulation of the IPA liquid and nitrogen is more precise; the IPA nozzle and the nitrogen nozzle are driven to rotate by the rotating arm, so that blowing back and forth between the center and the edge of the wafer can be achieved, which is conducive to the uniform distribution of the IPA liquid film and the drying of the IPA liquid film, avoiding leaving water marks and improving the drying effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the front view of a wafer drying device provided in an embodiment of the present invention; Figure 2 A schematic diagram of the temperature zone distribution of a heating plate used in an embodiment of the present invention; Figure 3 A schematic diagram of temperature distribution of a heating plate used in another embodiment of the present invention.

[0016] Description of reference numerals: 10- base 10; 20-rotating mechanism; 21-rotating shaft; 22-rotating chuck; 31-heating plate; 32-heating zone; 40-operating arm; 41-fixed arm; 42-rotating arm; 51-nitrogen pipeline; 52-nitrogen nozzle; 53-IPA pipeline; 54-IPA nozzle; 55-heating mechanism; 56-refrigeration mechanism. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0018] In the claims, description and the above-mentioned drawings of the present invention, unless otherwise clearly defined, the use of terms such as "first", "second" or "third" etc. are for distinguishing different objects rather than for describing a specific order.

[0019] Unless otherwise expressly defined, the directional words in the claims, specification and the above-mentioned drawings of the present invention, such as the use of terms such as "upper", "lower", "top", "bottom", "front", "back", "inside", "outside", "center", "lateral", "longitudinal", "horizontal", "vertical", "left", "right", "clockwise", "counterclockwise", "high", "low", etc., indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the specific protection scope of the present invention.

[0020] In the claims, specification and the above drawings of the present invention, unless otherwise clearly defined, if the term "fixed connection" or "fixed connection" is used, it should be understood in a broad sense, that is, any connection method without a displacement relationship and relative rotation relationship between the two, that is to say, including non-detachable fixed connection, detachable fixed connection, integrated connection and fixed connection through other devices or elements.

[0021] In the claims, description and drawings of the present invention, if the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0022] The wafer drying method provided by the present invention is now described. The wafer drying method comprises the following steps: S10: placing the wafer to be cleaned on the rotating chuck 22, the rotating chuck 22 drives the wafer to rotate at a first speed, and the cooled IPA liquid is sprayed toward the center of the wafer at a first flow rate until the entire wafer is covered; S20: reducing the flow rate of the IPA liquid to a second flow rate, spraying nitrogen gas at a preset temperature toward the center of the wafer, and blowing the nitrogen gas and the IPA liquid back and forth between the outer edge of the wafer and the center of the wafer; S30: a plurality of heating zones 32 are arranged at the bottom of the wafer along the direction from the inner circle to the outer circle, and the temperature of the plurality of heating zones 32 is successively reduced along the direction away from the wafer axis, so that the wafer is preliminarily dried; S40: Turn off nitrogen and IPA liquid purge, and rotate the chuck 22 to drive the wafer to rotate at a second rotation speed, which is greater than the first rotation speed, until the wafer is completely dry.

[0023] Compared with the prior art, the wafer drying method provided in this embodiment heats the bottom of the wafer in different zones so that the IPA liquid film formed on the wafer surface can generate a temperature gradient difference along the radial direction of the wafer. Since the surface tension of the IPA liquid varies with the temperature, the IPA liquid film can be orderly separated from the wafer surface by using the Marangoni effect combined with the centrifugal force of the low-speed rotation (first rotation speed) and the nitrogen purge, which can reduce the damage of the microstructure during the drying process, and the nitrogen purges the wafer after heating, which can increase the drying speed; the IPA liquid is initially sprayed onto the wafer at a first flow rate to quickly form a liquid film, and then the flow rate is reduced to a second flow rate during the nitrogen purge, which can help the IPA liquid film to be evenly distributed on the wafer surface, and the subsequent drying can also be fast; the wafer rotates at the first speed during the IPA and nitrogen purge and the zone heating, and the lower speed can avoid damage to the wafer surface, and then the nitrogen and IPA liquid purge are turned off, and the wafer is increased to the second speed, which can be rotated at a high speed to achieve fast drying of the wafer, and since no purge is performed at this time, surface damage of the wafer can also be avoided.

[0024] The difference between the highest temperature and the lowest temperature in the plurality of heating zones 32 is 50° C., which can achieve a better temperature gradient Marangoni effect.

[0025] Specifically, see Figure 3, multiple heating zones 32 form multiple temperatures from the center to the edge, each heating zone 32 corresponds to a temperature zone, and the difference between the inner and outer diameters of each heating zone 32 is the same or different (the inner diameter of the innermost heating zone 32 is 0). For example: the temperature zone is divided into the first temperature zone, the second temperature zone, the third temperature zone, and the fourth temperature zone, which are arranged in sequence along the direction away from the wafer axis. The first temperature zone is 65℃~80℃, the second temperature zone is 50℃~65℃, the third temperature zone is 35℃~50℃, and the fourth temperature zone is 25℃~35℃; the range of the first heating zone 32 (corresponding to the first temperature zone) is 0mm~45mm; the range of the second heating zone 32 (corresponding to the second temperature zone) is 45mm~90mm; the range of the third heating zone 32 (corresponding to the third temperature zone) is 90mm~120mm; the range of the fourth heating zone 32 (corresponding to the fourth temperature zone) is 120mm~150mm.

[0026] As a variant embodiment, see Figure 2 , multiple heating zones 32 form multiple temperatures from the center to the edge, multiple heating zones 32 form a temperature zone, each temperature includes the same or different number of heating zones 32, and the difference between the inner and outer diameters of each heating zone 32 is equal. A specific example is as follows: the temperature zones are divided into a first temperature zone, a second temperature zone, a third temperature zone, and a fourth temperature zone, which are arranged in sequence along a direction away from the wafer axis. The first temperature zone is 65°C~80°C, the second temperature zone is 50°C~65°C, the third temperature zone is 35°C~50°C, and the fourth temperature zone is 25°C~35°C; the heating zone 32 is divided into 10 (the first heating zone, the second heating zone, ..., the tenth heating zone), and the inner and outer diameter difference of each heating zone is 15mm. The 1st to 3rd heating zones constitute the first temperature zone, ranging from 0mm to 45mm; the 4th to 6th heating zones constitute the second temperature zone, ranging from 45mm to 90mm; the 7th to 8th heating zones constitute the third temperature zone, ranging from 90mm to 120mm; the 9th to 10th heating zones constitute the fourth temperature, ranging from 120mm to 150mm.

[0027] In the specific implementation process, the IPA flow rate (ie, the first flow rate) when IPA just starts to replace the DIW (deionized water) liquid film (ie, step S10) is 80 ml / min to 120 ml / min, and the wafer rotation speed (ie, the first rotation speed) is less than or equal to 500 rpm.

[0028] When the IPA liquid film covers the entire wafer surface and heating is completed, the nitrogen nozzle 52 moves from the first heating zone to the tenth heating zone at a speed of 1 mm / s to 4 mm / s. At this time, the IPA flow rate (i.e., the second flow rate) is 50 ml / min to 80 ml / min. After the IPA flow rate is reduced, the rotation speed of the wafer also changes accordingly. The wafer is reduced to the third rotation speed during steps S20 and S30. The third rotation speed is 300 rpm to 500 rpm, and the nitrogen purge flow rate is 4 L / min.

[0029] The temperature of the IPA liquid after cooling is 0℃~25℃, and the temperature of the nitrogen after heating (i.e. the preset temperature) is 65℃~80℃. Cooling the IPA before spraying can increase the temperature difference between the sprayed IPA liquid temperature and its own ignition point, thereby reducing the ignition probability of IPA and making it safer to use; by purging the nitrogen after heating, it is helpful to shorten the drying time and improve the drying efficiency.

[0030] Based on the same inventive concept, see Figure 1 The present application also provides a wafer drying device for implementing the above-mentioned wafer drying method, including a base 10, a rotating mechanism 20, a heating mechanism 55, an operating arm 40 and a spray assembly, wherein the rotating mechanism 20 is arranged on the base 10, a rotating chuck 22 is arranged on the top of the rotating mechanism 20, and a through hole is arranged in the middle of the rotating mechanism 20; the heating mechanism 55 is arranged on the base 10 and passes through the through hole, and the heating mechanism 55 has a heating disk 31 located below the rotating chuck 22, and the heating disk 31 has a plurality of heating zones 32 arranged from the inside to the outside; the operating arm 40 includes a heating plate 31 fixed to the base 10, a heating plate 31 having a plurality of heating zones 32 arranged from the inside to the outside, and a heating plate 31 having a plurality of heating zones 32 arranged from the inside to the outside; the operating arm 40 includes a heating plate 31 fixed to the base 10, a heating plate 31 having a plurality of heating zones 32 arranged from the inside to the outside, and a heating plate 31 having a plurality of heating zones 32 arranged from the inside to the outside; the heating plate 31 having a plurality of heating plates 31 fixed to the base 10, a heating plate 31 having a plurality of heating plates 31 arranged from the inside to the outside, and ... 0, and a rotating arm 42 fixedly connected to the top of the fixed arm 41, the fixed arm 41 extends up and down, and the rotating arm 42 extends horizontally, and the rotating arm 42 is used to rise and fall and rotate around the axial direction of the fixed arm 41; the spray assembly includes a nitrogen pipeline 51, a nitrogen nozzle 52 connected to the nitrogen pipeline 51, an IPA pipeline 53, and an IPA nozzle 54 connected to the IPA pipeline 53, the nitrogen nozzle 52 and the IPA nozzle 54 are both fixedly arranged at the free end of the rotating arm 42, the nitrogen pipeline 51 is provided with a heating mechanism 55, and the IPA pipeline 53 is provided with a cooling mechanism 56.

[0031] The specific operation process of the wafer drying device of this embodiment is as follows: the wafer is placed on the rotating chuck 22, the rotating chuck 22 drives the wafer to rotate, the rotating arm 42 drives the IPA nozzle 54 to move to the center of the wafer, the refrigeration mechanism 56 cools the IPA liquid and sprays the cooled IPA liquid to the center of the wafer, after the IPA liquid forms a uniform liquid film on the surface of the wafer, the nitrogen is heated by the heating mechanism 55 and sprayed to the center of the wafer, at this time, the rotating arm 42 drives the IPA nozzle 54 and the nitrogen nozzle 52 to rotate to achieve switching between the center and the edge of the wafer, and then the heating plate 31 is turned on to heat the wafer, and after heating for a period of time, the heating plate 31, the IPA nozzle 54, and the nitrogen nozzle 52 are turned off, and the rotation speed of the wafer is increased until it is completely dried.

[0032] Compared with the prior art, the device of the present application can heat the wafer while driving the wafer to rotate by setting a through hole on the rotating mechanism 20, so as to facilitate the temperature gradient control on the wafer; and a refrigeration mechanism 56 is set on the IPA pipeline 53 to cool the IPA liquid, and a heating mechanism 55 is set on the nitrogen pipeline 51 to keep the nitrogen at a constant temperature, which can be automatically achieved during the spraying process, and the temperature regulation of the IPA liquid and nitrogen is more accurate; the IPA nozzle 54 and the nitrogen nozzle 52 are driven to rotate by the rotating arm 42, so as to achieve back and forth blowing between the center and the edge of the wafer, which is conducive to the uniform distribution of the IPA liquid film and the drying of the IPA liquid film, avoiding leaving water marks and improving the drying effect.

[0033] In some embodiments, an improved implementation of the above-mentioned heating mechanism 55 is: the heating mechanism 55 also includes a temperature control module, the temperature control module includes a temperature sensor and a temperature controller, the temperature sensor is used to measure the temperature of each heating zone 32, and the temperature controller is used to control the temperature of each heating zone 32. By controlling the heating mechanism 55 through the temperature control module, the temperature of each heating zone 32 can be accurately controlled, and the temperature control module can be adjusted at any time during the operation to achieve the best temperature gradient effect, thereby facilitating the drying of the IPA liquid film on the wafer surface.

[0034] In some embodiments, a specific implementation of the rotating mechanism 20 can be as follows: Figure 1 See the structure shown. Figure 1 The rotating mechanism 20 includes a hollow rotating shaft 21 rotatably connected to the base 10, a motor drivingly connected to the rotating shaft 21, and a rotating chuck 22 fixedly arranged at the top of the rotating shaft 21. The through hole formed by the hollow rotating shaft 21 can facilitate the arrangement of the heating mechanism 55. When the motor is started, it drives the rotating shaft 21 to rotate, and the rotating shaft 21 drives the rotating chuck 22 to rotate, thereby realizing the rotation of the wafer.

[0035] The motor and the rotating shaft 21 may be directly connected or indirectly connected via a conveyor belt, gears, etc. The rotation speed and rotation direction of the wafer can be controlled by controlling the rotation speed of the motor, which facilitates operation.

[0036] Specifically, the heating mechanism 55 can be heated in a variety of ways, for example: Water bath heating method: heating the wafer by passing liquids of different temperatures into different heating zones 32 in the heating plate 31; Resistance heating method: current is passed through a high resistance material to generate heat, and the heating temperature is adjusted to be different in different heating zones 32; Infrared radiation heating method: heating is achieved by infrared heating elements that transfer heat by radiation, and the heating temperature is adjusted differently in different heating zones 32; Others include thermopile heating, etc.

[0037] As a specific description of the lifting and rotating process of the rotating arm 42: a cylinder can be set on the fixed arm 41, and a motor can be installed on the cylinder. The output shaft of the motor is vertically set and connected to the rotating arm 42, so that the rotating arm 42 can be driven to rotate when the motor is turned on, and the rotating arm 42 can be driven to lift when the cylinder is turned on.

[0038] The heating mechanism 55 can heat the nitrogen passing through the nitrogen pipeline 51 by means of electric heating or the like; the cooling mechanism 56 can cool the IPA liquid passing through the IPA pipeline 53 by means of structures such as phase change materials.

[0039] As a specific implementation step of the application embodiment, the following is an example: In the first step, the wafer to be cleaned is placed in the drying station with the front side facing up. After being clamped by the rotating chuck 22, the IPA liquid nozzle is moved to the center position by the rotating arm 42, and the wafer begins to rotate at a low speed (the speed is generally less than or equal to 500rpm). At the same time, the IPA liquid (temperature 0℃~25℃ adjustable) cooled by the refrigeration mechanism 56 is sprayed to the center of the wafer at the set temperature and flow rate (generally 80ml / min~120ml / min). Under the action of the centrifugal force of the wafer, the IPA liquid will replace the cleaned DIW and cover the entire wafer, completing the distribution of the IPA liquid film on the surface.

[0040] In the second step, after the IPA liquid film is distributed on the wafer, the IPA liquid flow rate is reduced (generally less than 80 ml / min), and the wafer rotation speed is reduced to 300 rpm to 500 rpm, which needs to be lower than the wafer rotation speed in the first step. The nitrogen temperature is raised to the set temperature (65°C to 80°C) through the heating mechanism 55, and the nitrogen is sprayed onto the surface of the IPA liquid film at a set flow rate, providing power for liquid film peeling through viscosity. At the same time, the nozzle module blows toward the edge of the wafer at a set speed, and the speed can be controlled in sections to achieve radial speed regulation.

[0041] In the third step, when the nitrogen nozzle 52 moves to the center of the wafer, the heating mechanism 55 is turned on according to the temperature and heating rate set in different areas (the number of the zones can be determined as needed), so that the liquid film temperature at the center of the wafer is high. Since the liquid film temperature at the edge of the wafer is low, a temperature gradient difference is formed, and the temperature gradient Marangoni effect is induced during the liquid film detachment process to promote drying. The IPA nozzle 54 and the nitrogen nozzle 52 continue to move from the center to the edge, and the nitrogen and IPA liquid cooperate with the wafer to rotate at a low speed to complete the orderly detachment and complete drying of the liquid film.

[0042] In the fourth step, when the IPA nozzle 54 and the nitrogen nozzle 52 are moved out of the wafer edge as a whole, the wafer completes the liquid film separation process, and the IPA liquid and the cooling device, the nitrogen and its heating device are turned off in sequence, and the wafer is accelerated to rotate (the rotation speed is usually less than 800rpm) and cooperates with the wafer zone heating device according to the set speed and time to complete the drying of the last extremely thin liquid film. Then the zone heating device is turned off and the wafer rotation is stopped.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wafer drying method, characterized in that: The steps include: S10: placing the wafer to be cleaned on a rotating chuck, the rotating chuck drives the wafer to rotate at a first speed, and the cooled IPA liquid is sprayed toward the center of the wafer at a first flow rate until the entire wafer is covered; S20: reducing the flow rate of the IPA liquid to a second flow rate, spraying nitrogen gas at a preset temperature toward the center of the wafer, and blowing the nitrogen gas and the IPA liquid back and forth between the outer edge of the wafer and the center of the wafer; S30: a plurality of heating zones are arranged at the bottom of the wafer along the direction from the inner circle to the outer circle, and the temperatures of the plurality of heating zones are successively reduced along the direction away from the wafer axis, so that the wafer is preliminarily dried; S40: Turn off the nitrogen and IPA liquid purge, and rotate the chuck to drive the wafer to rotate at a second speed, which is greater than the first speed, until the wafer is completely dry.

2. The wafer drying method according to claim 1, characterized in that: The difference between the highest temperature and the lowest temperature in the plurality of heating zones is 50°C.

3. The wafer drying method according to claim 1, characterized in that: The plurality of heating zones form a plurality of temperature zones from the center to the edge, and each heating zone corresponds to a temperature zone.

4. The wafer drying method according to claim 1, characterized in that: The plurality of heating zones form a plurality of temperature zones from the center to the edge, and the plurality of heating zones constitute a temperature zone, and the number of heating zones contained in each temperature zone is the same or different.

5. The wafer drying method according to claim 3 or 4, characterized in that: The temperature zones are divided into a first temperature zone, a second temperature zone, a third temperature zone, and a fourth temperature zone, which are arranged in sequence along a direction away from the wafer axis. The first temperature zone is 65°C~80°C, the second temperature zone is 50°C~65°C, the third temperature zone is 35°C~50°C, and the fourth temperature zone is 25°C~35°C.

6. The wafer drying method according to claim 1, characterized in that: The wafer rotates at a third speed in steps S20 and S30, the third speed is less than the first speed, the first speed is less than or equal to 500 rpm, the third speed is 300 rpm~500 rpm, and the second speed is lower than 800 rpm.

7. The wafer drying method according to claim 1, characterized in that: The first flow rate is 80 ml / min to 120 ml / min, and the second flow rate is 50 ml / min to 80 ml / min.

8. The wafer drying method according to claim 1, characterized in that: The temperature of the IPA liquid after refrigeration is 0℃~25℃, and the preset temperature is 65℃~80℃.

9. A wafer drying device, characterized in that: A method for drying a wafer according to any one of claims 1 to 8, comprising: Base; A rotating mechanism is arranged on the base, a rotating chuck is arranged on the top of the rotating mechanism, and a through hole is arranged in the middle of the rotating mechanism; A heating mechanism is disposed on the base and passes through the through hole, wherein the heating mechanism has a heating disk located below the rotating chuck, and the heating disk has a plurality of heating zones arranged from the inside to the outside; An operating arm, comprising a fixed arm fixed to the base, and a rotating arm fixed to the top of the fixed arm, the fixed arm extending up and down, the rotating arm extending horizontally, and the rotating arm being used to lift and lower and rotate around the axial direction of the fixed arm; The spray assembly comprises a nitrogen pipeline, a nitrogen nozzle connected to the nitrogen pipeline, an IPA pipeline, and an IPA nozzle connected to the IPA pipeline. The nitrogen nozzle and the IPA nozzle are both fixedly arranged at the free end of the rotating arm. A heating mechanism is arranged on the nitrogen pipeline, and a cooling mechanism is arranged on the IPA pipeline.

10. The wafer drying device according to claim 9, characterized in that: The heating mechanism further comprises a temperature control module, which comprises a temperature sensor and a temperature controller. The temperature sensor is used to measure the temperature of each heating zone, and the temperature controller is used to control the temperature of each heating zone.

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