Drying device and method used after wafer cleaning

Abstract

The embodiment of the invention provides a drying device and method used after wafer cleaning, and the device is characterized in that the top of a cavity is provided with a protection cover; the heating part is arranged on the inner side of the protecting cover and used for heating and conducting the heating heat to the interior of the cavity through the cavity wall of the cavity so as to maintain the temperature in the cavity within a preset temperature range suitable for drying the wafer; the chuck is arranged in the cavity and is used for horizontally placing a to-be-dried wafer and driving the to-be-dried wafer to rotate in the drying process; the nozzle is fixed on the inner side of the protective cover, the position of the nozzle is located between the protective cover and the wafer to be dried, the nozzle is used for spraying heated inert gas to the direction of the protective cover, and in the drying process, rotation of the chuck and spraying of the inert gas are carried out at the same time. According to the device, the watermark risk is reduced, the drying efficiency is improved, IPA is prevented from being used, and organic matter residues are avoided.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a drying device and method for wafers after cleaning. Background Art

[0002] In the semiconductor process, wafer drying, especially the drying of substrate polishing wafers, is the most difficult. It not only requires the surface to be dehydrated, but also avoids leaving any water marks on the surface. Uneven heating on the wafer surface may not only leave water marks, but also cause lattice deformation, inconsistent material properties and other problems.

[0003] There are three main ways to dry wafers: Spin Dry Mechanism: The wafer is rotated at high speed and moisture is removed.

[0004] Advantages: The equipment has simple structure and low price.

[0005] Problems: The center is dehydrated first, not all at the same time; and the dehydration is slow, and an oxide layer may form on the surface.

[0006] IPA Drying Mechanism: Displacement of water with IPA (isopropyl alcohol) vapor.

[0007] Advantages: Good for graphics.

[0008] Problems: Use of flammable chemicals, organic matter, residues.

[0009] Marangoni Drying Mechanism: When IPA and N2 are sprayed out from the rinse tank, the wafer is immediately pulled up from the pure water and the water is removed by the Marangoni force generated at this time.

[0010] Advantages: Reduced IPA usage and water stains.

[0011] Problems: low throughput and residual organic matter. Summary of the invention

[0012] In view of this, an embodiment of the present invention provides a drying device for wafers after cleaning, so as to solve the technical problems of low drying efficiency and organic residue in wafer drying in the prior art. The device comprises: A cavity 1, with a protective cover 2 on the top of the cavity; A heating component is disposed on the inner side of the protective cover 2, and is used to generate heat, and conduct the generated heat to the inside of the cavity 1 through the cavity wall of the cavity 1, so as to maintain the temperature in the cavity 1 within a preset temperature range suitable for drying wafers; The chuck 3 is arranged inside the cavity 1, and is used to horizontally place the wafer to be dried, and drive the wafer to be dried to rotate during the drying process; The nozzle 4 is fixed on the inner side of the protective cover 2. The nozzle 4 is located between the protective cover 2 and the wafer to be dried and is used to spray the heated inert gas toward the protective cover 2. During the drying process, the rotation of the chuck and the spraying of the inert gas are carried out simultaneously.

[0013] The embodiment of the present invention also provides a drying method for wafers after cleaning, so as to solve the technical problems of low drying efficiency and organic residue in wafer drying in the prior art. The method comprises: The top of the cavity used for drying is provided with a protective cover, and before the operation, the heating component in the protective cover generates heat to maintain the temperature in the cavity within a preset temperature range suitable for drying wafers; Before drying, the wafer to be dried is placed horizontally on a chuck inside the chamber; During drying, the wafer to be dried is driven to rotate by the chuck, and at the same time, the heated inert gas is sprayed above the wafer to be dried toward the protective cover through a nozzle; After drying, open the chamber door and take out the dried wafer.

[0014] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in the embodiments of this specification include at least: adding a heating component in the top cover of the cavity, and conducting heat to the inside of the cavity through the cavity wall to maintain the temperature in the cavity within a preset temperature range suitable for drying wafers, thereby ensuring the atmosphere for wafer drying; at the same time, the heated inert gas is sprayed toward the cover using evenly distributed fan-shaped nozzles, so that the sprayed hot inert gas is evenly distributed on the rotating wafer to maintain an inert environment. The above drying device for wafers after cleaning can quickly increase the wafer temperature while maintaining an inert environment while ensuring the uniformity of the wafer temperature, thereby reducing the risk of watermarks, improving drying efficiency, avoiding the use of IPA, and avoiding organic residues. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a structural schematic diagram of a drying device for wafer cleaning provided by an embodiment of the present invention; Figure 2is a schematic diagram of the distribution of a nozzle provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of the appearance of a drying device for wafer cleaning provided by an embodiment of the present invention; Figure 4 The present invention provides a flowchart of a method for drying a wafer after cleaning. DETAILED DESCRIPTION

[0017] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0018] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0019] In an embodiment of the present invention, a drying device for wafers after cleaning is provided. Figure 1 As shown, the device comprises: A cavity 1, with a protective cover 2 on the top of the cavity; A heating component is disposed on the inner side of the protective cover 2, and is used to generate heat, and conduct the generated heat to the inside of the cavity 1 through the cavity wall of the cavity 1, so as to maintain the temperature in the cavity 1 within a preset temperature range suitable for drying wafers; The chuck 3 is arranged inside the cavity 1, and is used to horizontally place the wafer to be dried, and drive the wafer to be dried to rotate during the drying process; The nozzle 4 is fixed on the inner side of the protective cover 2. The nozzle 4 is located between the protective cover 2 and the wafer to be dried and is used to spray the heated inert gas toward the protective cover 2. During the drying process, the rotation of the chuck and the spraying of the inert gas are carried out simultaneously.

[0020] Depend on Figure 1As shown, in an embodiment of the present invention, a heating component is added to the top cover of the cavity, and heat is transferred to the inside of the cavity through the cavity wall to maintain the temperature in the cavity within a preset temperature range suitable for drying wafers, thereby ensuring the atmosphere for wafer drying; at the same time, the heated inert gas is sprayed toward the cover using evenly distributed fan-shaped nozzles, so that the sprayed hot inert gas is evenly distributed on the rotating wafer to maintain an inert environment. The above-mentioned drying device for wafers after cleaning can quickly increase the wafer temperature while maintaining an inert environment while ensuring the uniformity of the wafer temperature, thereby reducing the risk of watermarks, improving the drying efficiency, avoiding the use of IPA, and avoiding organic residues.

[0021] In the specific implementation, the specific structural form of the chuck 3 is not specifically limited in this application, and it is sufficient that the wafer can be placed horizontally and driven or carried to rotate. Specifically, the support structure of the chuck 3 can be fixed to the inner bottom of the cavity 1, or to the inner side wall of the cavity 1, and the position of the chuck can be ensured to be located at the center of the cavity 1 or on the central axis.

[0022] In a specific implementation, the material of the cavity 1 can be 316L stainless steel.

[0023] In a specific implementation, the heating component can be a silicone heating pad, the heating power of which is 1-2 KW / h. The silicone heating pad is applied and sealed to the inner side of the protective cover 2, and an insulating component (for example, insulating cotton) is provided on the outer top of the protective cover 2 to avoid heat loss.

[0024] In a specific implementation, in order to ensure that the wafer is within the heating range, the distance between the protective cover 2 and the wafer to be dried can be within a range of 100-150 mm.

[0025] In a specific implementation, in order to ensure that the hot inert gas can be sprayed evenly, the nozzle 4 can be a fan-shaped nozzle with a spray angle of 80°-120°.

[0026] During specific implementation, in order to further quickly increase the wafer temperature while ensuring the uniformity of the wafer temperature, it is proposed that there are multiple nozzles 4, and the multiple nozzles 4 are evenly distributed in multiple directions. The spray angles of the nozzles 4 in the same direction intersect with each other without dead angles, and the airflow forms an X-shaped spray. The intersection of multiple directions and the center of the wafer to be dried are on the central axis of the cavity 1.

[0027] Specifically, the multiple directions can be symmetrical or asymmetrical, as long as they are evenly distributed. For example, Figure 2 As shown, the plurality of nozzles 4 are distributed in four directions, and the four directions are cross-symmetrical. In addition, for example, the nozzles 4 can also be distributed in six directions, eight directions, etc.

[0028] In specific implementation, the above device also includes: Four gas heaters, each gas heater provides hot inert gas for spraying the nozzle in one direction, and the length of the pipeline between the gas heater and the nozzle 4 is ≤50cm (such as Figure 1 As shown, a gas inlet 7 is provided on the side wall of the cavity 1, and the inert gas heated by the gas heater is provided to the nozzle 4 through a pipeline through the gas inlet. The pipeline is provided with a heat insulation component (for example, heat insulation cotton) for heat preservation. Specifically, the gas heater can be a gas heater with a power of 0.5-1KW.

[0029] In a specific implementation, the inert gas may be nitrogen, and the flow rate of the heated nitrogen sprayed by the nozzle 4 is in the range of 120-200 ml / min. The inside of the cavity 1 is at a positive pressure relative to the outside, ensuring that the cavity is an inert environment.

[0030] In specific implementation, the above device also includes: A first J-type thermocouple, disposed in the protective cover 2, for monitoring the temperature of the heating area of ​​the heating component in the protective cover 2; The temperature control component is used to control the heating power of the heating component based on the PID algorithm according to the temperature monitored by the first J-type thermocouple.

[0031] In a specific implementation, the temperature control component may be a component implemented by combining software and / or hardware.

[0032] When implementing it, Figure 1 , Figure 3 As shown, the above device also includes: A second J-type thermocouple 5 is disposed on the side wall of the cavity 1 and is used to monitor the internal temperature of the cavity 1; A chamber door 6, arranged on the side wall of the chamber 1, for providing a passage for taking the wafer to be dried into the chamber 1; An air outlet is arranged on the cavity wall of the cavity 1; The temperature control component is also used to control the closing of the cavity door 6 and the exhaust valve of the exhaust port during the drying process and the heat preservation process; and to control the opening angle of the exhaust valve of the exhaust port based on the PID algorithm according to the temperature monitored by the second J-type thermocouple 5.

[0033] In specific implementation, for example, if the temperature monitored by the second J-type thermocouple 5 exceeds a preset threshold, the exhaust port can be slowly opened by the temperature control component, and the opening size of the exhaust valve can be controlled by software to control the exhaust valve angle.

[0034] In specific implementation, the cavity door 6 and the exhaust port are interlocked with the temperature in the cavity 1. During the drying process and the heat preservation process, the temperature control component controls the cavity door 6 and the exhaust valve of the exhaust port to close. After the drying is completed, the cavity door 6 is controlled to open to take out the dried wafers.

[0035] In a specific implementation, the drying time may be about 30-60 seconds, and the gas temperature in the cavity 1 may be 40-50° C. (ie, the above-mentioned preset temperature range).

[0036] Based on the same inventive concept, an embodiment of the present invention further provides a drying method for wafers after cleaning, as described in the following embodiments. Since the principle of solving the problem by the drying method for wafers after cleaning is similar to that of the drying device for wafers after cleaning, the implementation of the drying method for wafers after cleaning can refer to the implementation of the drying device for wafers after cleaning, and the repeated parts will not be repeated.

[0037] Figure 4 is a flow chart of a method for drying wafers after cleaning according to an embodiment of the present invention. Figure 4 As shown, including: Step S401: There is a protective cover on the top of the chamber used for drying. Before the operation, the temperature in the chamber is maintained within a preset temperature range suitable for drying wafers by heating a heating component in the protective cover; Step S402: before drying, placing the wafer to be dried horizontally on a chuck inside the chamber; Step S403: During drying, the wafer to be dried is driven to rotate by the chuck, and at the same time, a heated inert gas is sprayed above the wafer to be dried toward the protective cover through a nozzle; Step S404: After drying, open the chamber door and take out the dried wafers.

[0038] The embodiments of the present invention achieve the following technical effects: a heating component is added to the top cover of the cavity, and heat is transferred to the inside of the cavity through the cavity wall to maintain the temperature in the cavity within a preset temperature range suitable for drying wafers, thereby ensuring the atmosphere for wafer drying; at the same time, the heated inert gas is sprayed toward the cover using evenly distributed fan-shaped nozzles, so that the sprayed hot inert gas is evenly distributed on the rotating wafer to maintain an inert environment. The above-mentioned drying device for wafers after cleaning can quickly increase the temperature of the wafer while maintaining an inert environment while ensuring the uniformity of the wafer temperature, thereby reducing the risk of watermarks, improving drying efficiency, avoiding the use of IPA, and avoiding organic residues.

[0039] Obviously, those skilled in the art should understand that the modules or steps of the above-mentioned embodiments of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, and optionally, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order from that here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. In this way, the embodiments of the present invention are not limited to any specific combination of hardware and software.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A drying device for wafers after cleaning, characterized in that: include: A cavity (1), wherein a protective cover (2) is provided on the top of the cavity; A heating component, arranged on the inner side of the protective cover (2), used for generating heat and conducting the generated heat to the interior of the cavity (1) through the cavity wall of the cavity (1), so as to maintain the temperature in the cavity (1) within a preset temperature range suitable for drying wafers; A chuck (3) is arranged inside the cavity (1) and is used to horizontally place the wafer to be dried and drive the wafer to be dried to rotate during the drying process; A nozzle (4) is fixed on the inner side of the protective cover (2), and the nozzle (4) is located between the protective cover (2) and the wafer to be dried, and is used to spray the heated inert gas in the direction of the protective cover (2), wherein during the drying process, the rotation of the chuck and the spraying of the inert gas are carried out simultaneously.

2. The drying device for wafer cleaning according to claim 1, characterized in that: The heating component is a silicone heating pad, the heating power of the silicone heating pad is 1-2 kW / h, the silicone heating pad is attached to and sealed on the inner side of the protective cover (2), and a heat insulating component is provided on the outer top of the protective cover (2).

3. The drying device for wafer cleaning according to claim 1, characterized in that: The distance between the protective cover (2) and the wafer to be dried is in the range of 100 mm to 150 mm.

4. The drying device for wafer cleaning according to claim 1, characterized in that: The nozzle (4) is a fan-shaped nozzle with a spray angle of 80°-120°.

5. The drying device for wafer cleaning according to claim 1, characterized in that: There are multiple nozzles (4), and the multiple nozzles (4) are evenly distributed in multiple directions. The spraying angles of the nozzles (4) in the same direction intersect with each other without dead angles, and the airflow forms an X-shaped spray. The intersection of the multiple directions and the center of the wafer to be dried are on the central axis of the chamber (1).

6. The drying device for wafer cleaning according to claim 5, characterized in that: Also includes: Four gas heaters, each gas heater provides hot inert gas for spraying to the nozzle in one direction, the length of the pipeline between the gas heater and the nozzle (4) is ≤50 cm, and a heat insulation component is provided on the pipeline.

7. The drying device for wafer cleaning according to claim 1, characterized in that: The inert gas is nitrogen, the flow rate of the heated nitrogen sprayed by the nozzle (4) is in the range of 120-200 ml / min, and the interior of the cavity (1) is at a positive pressure relative to the exterior.

8. The drying device for wafers after cleaning according to any one of claims 1 to 7, characterized in that: Also includes: A first J-type thermocouple, arranged in the protective cover (2), and used to monitor the temperature of a heating area of ​​the heating component in the protective cover (2); The temperature control component is used to control the heating power of the heating component based on the PID algorithm according to the temperature monitored by the first J-type thermocouple.

9. The drying device for wafer cleaning according to claim 8, characterized in that: Also includes: A second J-type thermocouple (5) is arranged on the side wall of the cavity (1) and is used to monitor the internal temperature of the cavity (1); A cavity door (6) is arranged on a side wall of the cavity (1) and is used to provide a passage for taking the wafer to be dried into and placing it in the cavity (1); An air outlet is arranged on the cavity wall of the cavity (1); The temperature control component is also used to control the closing of the cavity door (6) and the exhaust valve of the exhaust port during the drying process and the heat preservation process; and to control the opening angle of the exhaust valve of the exhaust port based on the PID algorithm according to the temperature monitored by the second J-type thermocouple (5).

10. A method for drying wafers after cleaning, characterized in that: include: The top of the cavity used for drying is provided with a protective cover, and before the operation, the heating component in the protective cover generates heat to maintain the temperature in the cavity within a preset temperature range suitable for drying wafers; Before drying, the wafer to be dried is placed horizontally on a chuck inside the chamber; During drying, the wafer to be dried is driven to rotate by the chuck, and at the same time, the heated inert gas is sprayed above the wafer to be dried toward the protective cover through a nozzle; After drying, open the chamber door and take out the dried wafer.

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