Wafer drying method and semiconductor process apparatus

Abstract

The present application relates to wafer drying technical field, specifically, it relates to a kind of wafer drying method and semiconductor process equipment.Wafer drying method includes: initial setting step, it is set to the positive pressure wind field of upper sending lower row in dry groove body and its adjacent groove body, and the wind speed in dry groove body is set to greater than the wind speed in adjacent groove body;Wafer washing step, wafer is placed in dry groove body, water is injected into dry groove body, until wafer is immersed in water;Drying setting step, dry gas is introduced into dry groove body, and the wind speed difference in dry groove body and adjacent groove is increased;Drying step, wafer is gradually exposed above water surface from top to bottom.The wafer drying method and semiconductor process equipment provided by the present application are beneficial to improve wafer cleanliness, improve cleaning and drying process effect, and water mark defects are not easy to produce in wafer edge or contact point, also have the advantages of strong process compatibility, high equipment stability.

Description

Technical Field

[0001] This invention relates to the field of wafer drying technology, and more specifically, to a wafer drying method and semiconductor process equipment. Background Technology

[0002] In semiconductor cleaning processes, the drying effect of wafers is crucial. If moisture remains on the wafer surface during the drying process, not only will the residual moisture make the wafer surface more susceptible to the formation of a natural oxide layer, but impurity particles or metal ions carried by the residual moisture may also redeposit on the wafer surface, resulting in uneven photoresist coating and severely affecting the structure and electrical characteristics of the device.

[0003] Currently, the Marangoni drying method is commonly used to dry wafers, which can significantly reduce the risk of moisture residue on the wafer surface. However, the process control of this technology is complex, and the wafer may be contaminated by particles in the airflow during the drying process. This results in insufficient stability in the removal of impurities and particles, leading to poor wafer cleanliness and making it difficult to meet the particle removal standards of advanced processes. Summary of the Invention

[0004] The purpose of this invention is to provide a wafer drying method and semiconductor process equipment to alleviate the technical problem of poor wafer cleanliness in existing wafer drying methods.

[0005] The wafer drying method provided by this invention includes:

[0006] In the initial setup step, the drying tank and its adjacent tanks are all set to a positive pressure air field with upward supply and downward exhaust, and the wind speed in the drying tank is set to be greater than the wind speed in the adjacent tanks.

[0007] The wafer washing step involves placing the wafer into the drying tank and filling the drying tank with water until the wafer is submerged in the water.

[0008] In the drying setup step, drying gas is introduced into the drying tank, and the wind speed difference between the drying tank and the adjacent tank is increased.

[0009] In the drying step, the wafer is gradually exposed above the water surface from top to bottom.

[0010] Preferably, as one possible implementation, in the initial setting step, the wind speed difference between the drying tank and the adjacent tank is a first wind speed difference value, and the ratio of the first wind speed difference value to the wind speed in the drying tank is 5~15%.

[0011] In the drying setup step, the wind speed difference between the drying tank and the adjacent tank is the second wind speed difference, and the ratio of the second wind speed difference to the wind speed in the drying tank is 15-30%.

[0012] Preferably, as one possible implementation, the difference between the suction velocity and the air supply velocity of the drying tank is the drying suction-suction difference, and the difference between the suction velocity and the air supply velocity of adjacent tanks is the adjacent suction-suction difference; the initial setting step further includes:

[0013] The air extraction speed of the drying tank is set to be greater than the air supply speed;

[0014] The ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank is set to be equal to the ratio of the drying extraction difference to the air supply velocity of the drying tank.

[0015] Preferably, as one possible implementation, the drying setting step further includes:

[0016] Increase the ratio of the drying extraction difference to the air supply velocity of the drying tank, and increase the ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank.

[0017] Preferably, as one possible implementation, the drying setting step includes:

[0018] Increase the air extraction speed of the drying tank and decrease the air supply speed of the adjacent tank.

[0019] Preferably, as one possible implementation, in the initial setting step, the ratio of the drying extraction difference to the air supply velocity of the drying tank is 5~15%, and the ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank is 5~15%.

[0020] In the drying setup step, the ratio of the drying extraction difference to the air supply velocity of the drying tank is 10-20%, and the ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank is 10-20%.

[0021] Preferably, as one possible implementation, the wind speed in the drying tank is 0.3~0.4m / s, and the wind speed in the adjacent tank is 0.2~0.3m / s.

[0022] Preferably, as one possible implementation, the drying step includes: lifting the wafer until the wafer is completely removed from the water surface;

[0023] Alternatively, the drying step may include: draining water from the drying tank until the wafer is fully exposed.

[0024] Preferably, as one possible implementation, the drying gas includes isopropanol and nitrogen.

[0025] Preferably, as one possible implementation, after the drying step, the method further includes:

[0026] The purging step involves purging the wafer with an inert gas.

[0027] Preferably, as one possible implementation, after the purging step, the method further includes:

[0028] The wind field in the drying tank and the wind field in the adjacent tank are restored to the wind field state in the initial setting step.

[0029] The semiconductor process equipment provided by the present invention includes a drying tank, an adjacent tank, a wafer driving assembly, an air supply assembly, an air extraction assembly, an air intake assembly, a water injection assembly, and a controller. The controller is characterized in that it includes at least one processor and at least one memory, the memory storing a computer program, which, when executed by the processor, implements the above-described wafer drying method.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This invention achieves differentiated airflow control by collaboratively controlling the airflow velocity within the drying tank and its adjacent tanks. This increases the airflow velocity difference between the drying tank and adjacent tanks during the wafer drying process, significantly reducing the impact of lateral airflow on the wafer. Consequently, particles are less likely to redeposit on the wafer after detaching from the wafer surface, reducing secondary deposition of impurities and improving particle removal stability. This meets the particle removal standards of advanced processes, improving wafer cleanliness and enhancing the cleaning and drying process. Furthermore, the airflow velocity is easier to control compared to adjusting other process parameters, reducing the likelihood of watermarks at wafer edges or contact points. This reduces wafer contamination by impurities, improves drying uniformity, and offers advantages such as strong process compatibility and high equipment stability. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 This is a first schematic flowchart of a wafer drying method provided in an embodiment of the present invention;

[0034] Figure 2 This is a second schematic flowchart of a wafer drying method provided in an embodiment of the present invention;

[0035] Figure 3This is a schematic diagram of the structure of a semiconductor process equipment provided in an embodiment of the present invention. Detailed Implementation

[0036] In related technologies, during the removal of impurities from the wafer surface and the drying of the wafer using the Marangoni drying method, the airflow within the drying process area is constant. To achieve a balance between process parameters such as wafer pulling speed, air velocity, and drying gas flow rate, complex process control is required to avoid watermark defects at wafer edges or contact points, which can lead to impurity particle contamination and uneven drying. Furthermore, under constant airflow conditions, the wafer drying process may be affected by lateral airflow, causing particles that were originally removed from the wafer surface to redeposit onto the wafer, resulting in secondary wafer contamination and making it difficult to meet the particle removal standards of advanced processes.

[0037] Based on this, the present invention provides a wafer drying method that reduces impurity particles attached to the wafer by coordinating the airflow in the drying process area and its adjacent process area (generally a wet cleaning area), thereby improving the cleanliness of the wafer after cleaning and drying and meeting the particle removal standards of advanced processes.

[0038] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0040] Figure 1 A schematic flowchart of a wafer drying method provided for one embodiment of the present invention, the method comprising:

[0041] S102, Initial setup step: Set the drying tank and its adjacent tanks to a positive pressure airflow field with upward supply and downward exhaust, and set the wind speed in the drying tank to be greater than the wind speed in the adjacent tanks.

[0042] After the initial setup of the airflow is completed, the pressure at the top of the tank is higher than the pressure at the bottom, creating a microenvironment that allows gas to flow from top to bottom. The gas introduced into the tank can be compressed air that meets the required cleanliness level.

[0043] S104, Wafer washing step: Place the wafer into the drying tank and fill the drying tank with water until the wafer is submerged in the water.

[0044] The water flow rinses the wafer, removing solvents and impurity particles from the wafer surface; specifically, the water flow can be injected from the bottom and side of the drying tank.

[0045] S106, Drying setup step: Introduce drying gas into the drying tank and increase the wind speed difference between the drying tank and the adjacent tank.

[0046] S108, the drying step, gradually exposes the wafer above the water surface from top to bottom.

[0047] As the wafer is gradually exposed above the water surface from top to bottom, the drying gas reacts with the aqueous film adhering to the wafer surface via the Marangoni reaction. The drying liquid film formed by the drying gas gradually replaces the aqueous film on the wafer surface. After the wafer is fully exposed, the wafer surface will be covered with a complete drying liquid film, thus achieving wafer drying.

[0048] This embodiment achieves differentiated airflow control by coordinating the airflow velocity within the drying tank and its adjacent tanks. This increases the airflow velocity difference between the drying tank and adjacent tanks during the wafer drying process, significantly reducing the impact of lateral airflow on the wafer. Consequently, particles are less likely to re-deposit onto the wafer after detaching from the wafer surface, reducing secondary deposition of impurities and improving particle removal stability. This meets the particle removal standards of advanced processes, improving wafer cleanliness and enhancing the cleaning and drying process. Furthermore, airflow velocity is easier to control compared to adjusting other process parameters, reducing the likelihood of watermark defects at wafer edges or contact points. This makes the wafer less susceptible to impurity contamination, resulting in better drying uniformity. It also offers advantages such as strong process compatibility and high equipment stability.

[0049] In the initial setup step, the wind speed difference between the drying tank and the adjacent tank is defined as the first wind speed difference, and the ratio of the first wind speed difference to the wind speed in the drying tank is set to 5~15%. In the drying setup step, the wind speed difference between the drying tank and the adjacent tank is defined as the second wind speed difference, and the ratio of the second wind speed difference to the wind speed in the drying tank is set to 15~30%. This can effectively reduce the secondary deposition of impurity particles during wafer drying and prevent watermark defects from easily occurring at wafer edges or contact points.

[0050] The difference between the air extraction speed and the air supply speed of the drying tank is defined as the drying extraction-supply difference, and the difference between the air extraction speed and the air supply speed of adjacent tanks is defined as the adjacent extraction-supply difference.

[0051] The initial setup step described above may also include the following steps: setting the extraction speed of the drying tank to be greater than the supply air speed, so that convection is less likely to form inside the drying tank, and particles in the environment are less likely to be scattered. Additionally, the initial setup step may also include the following steps: setting the ratio of the difference between adjacent extraction speeds to the supply air speed of adjacent tanks to be equal to the ratio of the difference between the drying extraction speeds to the supply air speed of the drying tank, to facilitate airflow control.

[0052] The aforementioned drying setup may further include the following steps: increasing the ratio of the drying extraction difference to the air supply velocity of the drying tank to further reduce the risk of convection within the drying tank, resulting in more stable particle dynamics in the environment and making it less likely for particles to adhere to the wafer surface. Correspondingly, increasing the ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank ensures that this ratio always equals the ratio of the drying extraction difference to the air supply velocity of the drying tank, facilitating airflow control.

[0053] In the drying setup steps described above, the difference between the suction speed and the supply air speed of the drying tank (i.e., the drying suction-supply difference) can be increased by increasing the suction speed of the drying tank, thereby increasing the ratio of the drying suction-supply difference to the supply air speed of the drying tank. Alternatively, the difference between the suction speed and the supply air speed of adjacent tanks (i.e., the adjacent suction-supply difference) can be increased by decreasing the supply air speed of adjacent tanks, thereby increasing the ratio of the adjacent suction-supply difference to the supply air speed of adjacent tanks. This also simultaneously increases the air velocity difference between the drying tank and adjacent tanks.

[0054] Specifically, the ratio of the drying extraction difference to the air supply velocity of the drying tank in the initial setup step is set to 5-15%, preferably 10%; the ratio of the drying extraction difference to the air supply velocity of the drying tank in the drying setup step is set to 10-20%, preferably 15%. This ensures that excessive air supply velocity will not cause convection within the drying tank, nor will excessively low air supply velocity or excessively high extraction velocity lead to an unbalanced airflow within the drying tank. Correspondingly, the ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank in the initial setup step is set to 5-15%, preferably 10%; the ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank in the drying setup step is set to 10-20%, preferably 15%, ensuring that the ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank is always equal to the ratio of the drying extraction difference to the air supply velocity of the drying tank, facilitating airflow control.

[0055] Preferably, the wind speed inside the drying tank is set to 0.3~0.4 m / s, and the wind speed inside the adjacent tank is set to 0.2~0.3 m / s, which can meet the requirements of drying and wind field balance.

[0056] In the drying step described above, it is preferable to gradually pull the wafer out of the water by lifting it until the wafer is completely removed from the water surface, which is beneficial to the continuity of the operation; of course, the water level can also be gradually lowered by draining the water in the drying tank to expose the wafer until the wafer is completely exposed.

[0057] The aforementioned drying gases may specifically include isopropyl alcohol (IPA, chemical formula C3H8O) and nitrogen. During the drying process, N2 can drive IPA, causing the IPA liquid film to gradually replace the original aqueous film on the wafer surface, resulting in a better drying effect.

[0058] Following the drying step, the method provided in this embodiment further includes a purging step, in which an inert gas is used to purge the wafer to remove residual solvents on the wafer surface, prevent condensation, and ensure that the wafer is thoroughly dried.

[0059] After the purging step, the method provided in this embodiment further includes: restoring the wind field in the drying tank and the wind field in the adjacent tank to the wind field state in the initial setting step.

[0060] Figure 2 A schematic flowchart of a wafer drying method provided for one embodiment of the present invention, the method comprising:

[0061] S202, Initial Wind Field Setup

[0062] The drying tank and its adjacent tanks are all configured with a slightly positive pressure airflow field, with the airflow velocity in the drying tank being greater than that in the adjacent tanks. This prevents airflow imbalance from creating eddies that could lead to incomplete drying or particle accumulation. During this process, the airflow velocity in the drying tank is 10% higher than that in the adjacent tanks; the exhaust velocity of the drying tank is also 10% higher than the supply velocity.

[0063] S204, wafer loading

[0064] A robotic arm is used to remove the wafer from the cleaning tank and place it into the drying tank. The bottom and side water flows are turned on to continuously rinse and remove the solvent from the wafer surface, carrying away impurity particles until the wafer is completely submerged in water.

[0065] S206, drying process

[0066] Reduce the air velocity in adjacent tanks (preferably by reducing the supply air velocity) to make the extraction velocity 15% higher than the supply air velocity; simultaneously increase the extraction velocity in the drying tank to make it 15% higher than the supply air velocity, resulting in an air velocity 20% higher in the drying tank than in adjacent tanks, thus achieving a differentiated airflow pattern in the drying area. Slowly raise the wafer while activating IPA / N2. As the wafer rises from the water, the IPA liquid film gradually replaces the original aqueous film on the wafer surface, ensuring a complete IPA liquid film covers the wafer surface.

[0067] S208, Gas purging

[0068] Inert gas is used to purge and remove residual solvent from the wafer surface to prevent condensation and ensure thorough drying. The airflow in the drying tank and adjacent tanks is gradually restored to its original level.

[0069] Figure 3 An embodiment of the present invention provides a semiconductor process apparatus 300, which includes a drying tank 310, an adjacent tank (not shown in the figure), a wafer driving assembly (not shown in the figure), an air supply assembly 320, an air extraction assembly 330, an air intake assembly 340, a water injection assembly 350, and a controller. The controller includes at least one processor and at least one memory, the memory storing a computer program, which, when executed by the processor, implements the method of any of the above embodiments.

[0070] For example, the controller can be a host computer or a slave computer. The controller can control the air supply assembly 320 to supply air to the drying tank 310 and its adjacent tanks, and can also control the air extraction assembly 330 to extract air from the drying tank 310 and its adjacent tanks, thereby controlling the airflow inside the drying tank 310 and its adjacent tanks and removing reaction byproducts. The controller can control the opening of the valve of the air inlet assembly 340 to introduce the corresponding process gas into the drying tank 310; the controller can also control the opening degree of the valve of the air inlet assembly 340 to control the flow rate of the process gas (e.g., drying gas). The controller can control the opening of the valve of the water injection assembly 350 to inject water into the drying tank 310.

[0071] The controller can control the movement of the wafer drive assembly to remove the wafer 360 from the cleaning process tank and place it into the drying tank 310. The wafer drive assembly may include a robotic arm.

[0072] The semiconductor process equipment 300 in this application embodiment can be a Marangoni dryer. This application embodiment does not limit the type of semiconductor process equipment 300.

[0073] The semiconductor process equipment 300 provided in this embodiment of the invention has the same technical features as the wafer drying method provided in the above embodiment, so it can also solve the same technical problems and achieve the same technical effects.

[0074] This embodiment also provides a machine-readable storage medium storing machine-executable instructions. When the machine-executable instructions are called and executed by a processor, the machine-executable instructions cause the processor to implement the above-described wafer drying method.

[0075] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described equipment and apparatus can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0076] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0077] In the description of this invention, it should be noted that the terms "upper," "lower," and "inner," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wafer drying method, characterized in that, include: In the initial setup step, the drying tank and its adjacent tanks are all set to a positive pressure air field with upward supply and downward exhaust, and the wind speed in the drying tank is set to be greater than the wind speed in the adjacent tanks. The wafer washing step involves placing the wafer into the drying tank and filling the drying tank with water until the wafer is submerged in the water. In the drying setup step, drying gas is introduced into the drying tank, and the wind speed difference between the drying tank and the adjacent tank is increased. In the drying step, the wafer is gradually exposed above the water surface from top to bottom.

2. The wafer drying method according to claim 1, characterized in that, In the initial setup step, the wind speed difference between the drying tank and the adjacent tank is a first wind speed difference value, and the ratio of the first wind speed difference value to the wind speed in the drying tank is 5~15%; In the drying setup step, the wind speed difference between the drying tank and the adjacent tank is the second wind speed difference, and the ratio of the second wind speed difference to the wind speed in the drying tank is 15-30%.

3. The wafer drying method according to claim 1, characterized in that, The difference between the air extraction speed and the air supply speed of the drying tank is the drying extraction-supply difference, and the difference between the air extraction speed and the air supply speed of adjacent tanks is the adjacent extraction-supply difference. The initial setup step also includes: The air extraction speed of the drying tank is set to be greater than the air supply speed; The ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank is set to be equal to the ratio of the drying extraction difference to the air supply velocity of the drying tank.

4. The wafer drying method according to claim 3, characterized in that, The drying setup step also includes: Increase the ratio of the drying extraction difference to the air supply velocity of the drying tank, and increase the ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank.

5. The wafer drying method according to claim 4, characterized in that, The drying setup step includes: Increase the air extraction speed of the drying tank and decrease the air supply speed of the adjacent tank.

6. The wafer drying method according to claim 4, characterized in that, In the initial setup step, the ratio of the drying extraction difference to the air supply velocity of the drying tank is 5-15%, and the ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank is 5-15%. In the drying setup step, the ratio of the drying extraction difference to the air supply velocity of the drying tank is 10-20%, and the ratio of the adjacent extraction difference to the air supply velocity of the adjacent tank is 10-20%.

7. The wafer drying method according to claim 1, characterized in that, The wind speed inside the drying tank is 0.3~0.4 m / s, and the wind speed inside the adjacent tank is 0.2~0.3 m / s.

8. The wafer drying method according to claim 1, characterized in that, The drying step includes: lifting the wafer until the wafer is completely removed from the water surface; Alternatively, the drying step may include: draining water from the drying tank until the wafer is fully exposed.

9. The wafer drying method according to claim 1, characterized in that, The drying gas includes isopropanol and nitrogen.

10. The wafer drying method according to claim 1, characterized in that, Following the drying step, the method further includes: The purging step involves purging the wafer with an inert gas.

11. The wafer drying method according to claim 10, characterized in that, Following the purging step, the method further includes: The wind field in the drying tank and the wind field in the adjacent tank are restored to the wind field state in the initial setting step.

12. A semiconductor process apparatus, comprising a drying tank, adjacent tanks, a wafer driving assembly, an air supply assembly, an exhaust assembly, an air intake assembly, a water injection assembly, and a controller, characterized in that, The controller includes at least one processor and at least one memory, the memory storing a computer program that, when executed by the processor, implements the wafer drying method as described in any one of claims 1-11.

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