Wafer drying method and semiconductor process equipment

Abstract

The invention relates to the technical field of wafer drying, in particular to a wafer drying method and semiconductor process equipment. The wafer drying method comprises the following steps: an initial setting step: setting a drying groove body and an adjacent groove body into an upper-feeding and lower-discharging positive pressure wind field, and setting the wind speed in the drying groove body to be greater than the wind speed in the adjacent groove body; a wafer washing step: putting the wafer into the drying tank body, and injecting water into the drying tank body until the wafer is immersed in the water; in the drying setting step, dry gas is introduced into the drying groove body, and the air speed difference value between the drying groove body and the adjacent groove body is increased; and a drying step: gradually exposing the wafer above the water surface from top to bottom. According to the wafer drying method and the semiconductor process equipment provided by the invention, the wafer cleanliness is improved, the cleaning and drying process effect is improved, water mark defects are not easy to generate at the edge or the contact point of the wafer, and the wafer drying method and the semiconductor process equipment have the advantages of high process compatibility and high equipment stability.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer drying, and in particular to a wafer drying method and semiconductor process equipment. Background Art

[0002] Wafer drying is crucial in the semiconductor cleaning process. If moisture remains on the wafer surface during the drying process, it not only makes the natural oxide layer more likely to form on the wafer surface, but also carries impurity particles or metal ions that may redeposit on the wafer surface, resulting in uneven photoresist coating and seriously affecting the device's structure and electrical properties.

[0003] Currently, wafers are typically dried using the Marangoni drying method, which significantly reduces the risk of residual moisture on the wafer surface. However, this technique is complex to control and can lead to contamination from particles in the wind during the drying process. This leads to insufficient stability in particle removal, resulting in poor wafer cleanliness and difficulty meeting particle removal standards for advanced manufacturing processes. Summary of the Invention

[0004] The object of the present invention is to provide a wafer drying method and semiconductor process equipment to alleviate the technical problem of poor wafer cleanliness existing in the wafer drying method in the prior art.

[0005] The wafer drying method provided by the present invention comprises:

[0006] In an initial setting step, the drying tank body and its adjacent tank bodies are both set to a positive pressure wind field with upward delivery and downward exhaust, and the wind speed in the drying tank body is set to be greater than the wind speed in the adjacent tank bodies;

[0007] a wafer water washing step, placing the wafer into the drying tank body and injecting water into the drying tank body until the wafer is immersed in water;

[0008] In a drying setting step, dry gas is introduced into the drying tank body, and the wind speed difference between the drying tank body and the adjacent tank body is increased;

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

[0010] Preferably, as an implementable method, in the initial setting step, the wind speed difference between the drying tank body and the adjacent tank body is a first wind speed difference, and the ratio of the first wind speed difference to the wind speed in the drying tank body is 5-15%.

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

[0012] Preferably, as an implementable embodiment, the difference between the exhaust speed and the air supply speed of the drying trough is the drying exhaust speed difference, and the difference between the exhaust speed and the air supply speed of adjacent troughs is the adjacent exhaust speed 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 pumping difference to the air supply speed of the adjacent troughs is set to be equal to the ratio of the drying pumping difference to the air supply speed of the drying trough.

[0015] Preferably, as an implementable embodiment, the drying setting step further includes:

[0016] Increase the ratio of the drying pumping difference to the air supply speed of the drying trough body, and increase the ratio of the adjacent pumping differences to the air supply speed of the adjacent trough bodies.

[0017] Preferably, as an implementable embodiment, the drying setting step includes:

[0018] Increase the air extraction speed of the drying trough body and reduce the air supply speed of the adjacent trough body.

[0019] Preferably, as an implementable embodiment, in the initial setting step, the ratio of the drying pumping difference to the air supply speed of the drying trough body is 5-15%, and the ratio of the adjacent pumping differences to the air supply speed of the adjacent trough bodies is 5-15%.

[0020] In the drying setting step, the ratio of the drying pumping difference to the air supply speed of the drying trough is 10-20%, and the ratio of the adjacent pumping differences to the air supply speed of the adjacent troughs is 10-20%.

[0021] Preferably, as an implementable embodiment, the wind speed in the drying tank body is 0.3-0.4 m / s, and the wind speed in the adjacent tank body is 0.2-0.3 m / s.

[0022] Preferably, as an implementable embodiment, the drying step includes: lifting the wafer until the wafer is completely out of the water;

[0023] Alternatively, the drying step includes draining water from the drying tank until the wafers are completely exposed.

[0024] Preferably, as an implementable embodiment, the drying gas includes isopropyl alcohol and nitrogen.

[0025] Preferably, as an embodiment, after the drying step, the method further comprises:

[0026] In the purge step, the wafer is purged with an inert gas.

[0027] Preferably, as an embodiment, after the purge step, the method further comprises:

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

[0029] The semiconductor process equipment provided by the present invention includes a drying trough body, adjacent trough bodies, a wafer drive assembly, an air supply assembly, an exhaust assembly, an air intake assembly, a water injection assembly and a controller, and is characterized in that the controller includes at least one processor and at least one memory, and a computer program is stored in the memory, and when the computer program is executed by the processor, the above-mentioned wafer drying method is implemented.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention realizes differentiated wind field control by collaboratively controlling the wind speed in the drying trough and its adjacent troughs, increasing the wind speed difference between the drying trough and the adjacent troughs during the wafer drying process in the drying setting step, and can greatly reduce the impact of the lateral wind field on the wafer during the wafer drying process. As a result, during the drying process, particles are not easily redeposited on the wafer after leaving the wafer surface, reducing the secondary deposition of impurity particles, and having better stability in impurity particle removal, which can meet the particle removal standards of advanced processes, and is conducive to improving wafer cleanliness and enhancing the cleaning and drying process effect. In addition, wind speed is easier to control than adjusting other process parameters, and water mark defects are not easily generated at the edge or contact point of the wafer. Therefore, the wafer is not easily contaminated by impurity particles, and the drying uniformity is better. It also has the advantages of strong process compatibility and high equipment stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0033] Figure 1 A first schematic flow chart of a wafer drying method provided in an embodiment of the present invention;

[0034] Figure 2 A second schematic flow chart of a wafer drying method provided in an embodiment of the present invention;

[0035] Figure 3A schematic structural diagram of semiconductor process equipment provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In the related art, during the process of removing impurities from the wafer surface and drying the wafer using the Marangoni drying method, the wind field in the drying process area is constant. In order to achieve a balance between process parameters such as wafer pulling speed, wind speed, and drying gas flow rate, complex process control is required to avoid water mark defects at the edge or contact point of the wafer, causing impurity particle contamination and uneven drying problems; in addition, under a constant wind field, during the wafer drying process, it may be affected by the lateral wind field, causing particles that originally detached from the wafer surface to be redeposited on the wafer, resulting in secondary contamination of the wafer, making it difficult to meet the particle removal standards of advanced processes.

[0037] Based on this, the present invention provides a wafer drying method, which reduces the impurity particles attached to the wafer by collaboratively controlling the wind field of the drying process area and its adjacent process area (generally the wet cleaning area), so as to improve the cleanliness of the wafer after cleaning and drying, and meet the particle removal standards of advanced processes.

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0039] The present invention will be further described in detail below through specific implementation examples in conjunction with the accompanying drawings.

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

[0041] S102, an initial setting step, sets the drying trough and its adjacent troughs to a positive pressure wind field with upward delivery and downward exhaust, and sets the wind speed in the drying trough to be greater than the wind speed in the adjacent troughs.

[0042] After the initial setup of the wind farm is complete, the pressure above the trough is higher than the pressure below, creating a microenvironment that allows gas to flow from top to bottom. The gas fed into the trough can be compressed air of a cleanliness level that meets the required standards.

[0043] S104, wafer water washing step, placing the wafer into the drying tank body, and injecting water into the drying tank body until the wafer is immersed in water.

[0044] The water flow rinses the wafer to remove the solvent and foreign particles on the surface of the wafer; specifically, the water flow can be injected from the bottom and side of the drying tank.

[0045] S106, a drying setting step, introduces dry air into the drying tank body and increases the wind speed difference between the drying tank body and the adjacent tank bodies.

[0046] S108, a 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 will undergo a Marangoni reaction with the water film attached to the wafer surface. The drying liquid film formed by the drying gas will gradually replace the water film on the wafer surface. After the wafer is completely exposed, the wafer surface will be covered with a complete drying liquid film, thereby achieving wafer drying.

[0048] This embodiment achieves differentiated wind field control by collaboratively controlling the wind speed in the drying trough and its adjacent troughs, increasing the wind speed difference between the drying trough and the adjacent troughs during the wafer drying process in the drying setting step. This can greatly reduce the impact of the lateral wind field on the wafer during the wafer drying process. As a result, during the drying process, particles are less likely to re-deposit on the wafer after detaching from the wafer surface, reducing the secondary deposition of impurity particles. The impurity particle removal is more stable and can meet the particle removal standards of advanced processes, which is beneficial to improving the cleanliness of the wafer and enhancing the cleaning and drying process effect. In addition, the wind speed is easier to control than adjusting other process parameters, and water mark defects are less likely to occur at the edge or contact point of the wafer. As a result, the wafer is less likely to be contaminated by impurity particles, and the drying uniformity is better. It also has the advantages of strong process compatibility and high equipment stability.

[0049] In the initial setting step, the wind speed difference between the drying trough body and the adjacent trough body is defined as the first wind speed difference, and the ratio of the first wind speed difference to the wind speed inside the drying trough body is set to 5-15%; in the drying setting step, the wind speed difference between the drying trough body and the adjacent trough body is defined as the second wind speed difference, and the ratio of the second wind speed difference to the wind speed inside the drying trough body is set to 15-30%, which can effectively reduce the secondary deposition of impurity particles during the wafer drying process, and is less likely to produce water mark defects at the edge or contact point of the wafer.

[0050] The difference between the exhaust speed and the air supply speed of the drying trough is defined as the drying extraction difference, and the difference between the exhaust speed and the air supply speed of adjacent troughs is defined as the adjacent extraction difference.

[0051] The initial setup step may further include the following steps: setting the extraction speed of the drying trough to be greater than the air supply speed. This prevents convection from forming within the drying trough, and particles in the environment from being carried everywhere. Furthermore, the initial setup step may further include the following steps: setting the ratio of the difference in adjacent extraction speeds to the air supply speeds of adjacent troughs to be equal to the ratio of the difference in drying extraction speeds to the air supply speeds of the drying troughs, to facilitate wind field control.

[0052] The drying configuration step may also include increasing the ratio of the drying pumping differential to the air supply speed of the drying trough to further reduce the risk of convection within the drying trough. This stabilizes the dynamics of particles in the environment and makes them less likely to adhere to the wafer surface. Accordingly, the ratio of adjacent pumping differentials to the air supply speeds of adjacent troughs is increased so that the ratio is always equal to the ratio of the drying pumping differential to the air supply speed of the drying trough, facilitating wind field control.

[0053] In the drying setting step described above, the difference between the drying trough's exhaust speed and the air supply speed (i.e., the drying exhaust difference) can be increased by increasing the exhaust speed of the drying trough, thereby increasing the ratio of the drying exhaust difference to the drying trough's air supply speed. Alternatively, the difference between the exhaust speed and air supply speed of adjacent troughs (i.e., the adjacent exhaust difference) can be increased by reducing the air supply speed of adjacent troughs, thereby increasing the ratio of the adjacent exhaust difference to the adjacent trough's air supply speed. In this way, the wind speed difference between the drying troughs and adjacent troughs can also be simultaneously increased.

[0054] Specifically, the ratio of the drying pumping difference in the initial setting step to the air supply speed of the drying trough is set to 5-15%, preferably 10%; the ratio of the drying pumping difference in the drying setting step to the air supply speed of the drying trough is set to 10-20%, preferably 15%. In this way, convection will not form in the drying trough due to an excessively high air supply speed, nor will the wind field in the drying trough be unbalanced due to an excessively low air supply speed and an excessively high air extraction speed. Accordingly, the ratio of the adjacent pumping difference in the initial setting step to the air supply speed of adjacent troughs is set to 5-15%, preferably 10%; the ratio of the adjacent pumping difference in the drying setting step to the air supply speed of adjacent troughs is set to 10-20%, preferably 15%. This ensures that the ratio of the adjacent pumping difference to the air supply speed of adjacent troughs is always equal to the ratio of the drying pumping difference to the air supply speed of the drying trough, making it easier to control the wind field.

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

[0056] In the above-mentioned drying step, it is preferred to gradually pull the wafer out of the water by lifting the wafer until the wafer is completely out of the water surface, which is conducive to the continuity of the action; of course, the water level can also be gradually lowered to expose the wafer by draining the water in the drying tank until the wafer is completely exposed.

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

[0058] After the drying step, the method provided in this embodiment further includes a purging step, in which the wafer is purged with an inert gas to remove residual solvent on the surface of the wafer, prevent condensation, and ensure that the wafer is thoroughly dried.

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

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

[0061] S202, initial setting of wind farm

[0062] The drying trough and its adjacent troughs are both equipped with a slightly positive pressure wind field with upward delivery and downward exhaust. The wind speed inside the drying trough is set higher than that in adjacent troughs to avoid eddy currents caused by an unbalanced wind field, which can lead to incomplete drying or particle accumulation. During this process, the wind speed inside the drying trough is 10% higher than that in adjacent troughs; the exhaust speed of the drying trough is 10% higher than the air supply speed, and the exhaust speed of the drying trough is also 10% higher than the air supply speed.

[0063] S204, wafer loading

[0064] Use a robotic arm to remove the wafer from the cleaning process tank and place it in the drying tank. Turn on the water flow from the bottom and side, and use the water flow to continuously rinse and remove the solvent on the wafer surface and take away the impurity particles on the wafer surface until the water surface completely submerges the wafer.

[0065] S206, drying process

[0066] Reduce the air speed in adjacent troughs (preferably by reducing the air supply speed) to a 15% higher extraction speed than the air supply speed. Simultaneously, increase the extraction speed in the drying trough to a 15% higher extraction speed than the air supply speed. The wind speed within the drying trough should be 20% higher than that within the adjacent troughs, achieving differentiated wind fields within the drying area. Slowly elevate the wafer while operating the IPA / N2 system. As the wafer rises from the water, the IPA film gradually replaces the existing water film on the wafer surface, leaving a complete IPA film covering the wafer surface.

[0067] S208, gas purge

[0068] Use inert gas to purge and remove residual solvents on the wafer surface to prevent condensation and ensure thorough drying. The wind field of the drying tank and adjacent tanks gradually returns to its original level.

[0069] Figure 3 A semiconductor process equipment 300 is provided for an embodiment of the present invention, which includes a drying trough body 310, an adjacent trough body (not shown in the figure), a wafer drive assembly (not shown in the figure), an air supply assembly 320, an exhaust 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, and a computer program is stored in the memory. When the computer program is executed by the processor, a method of any of the above-mentioned embodiments is implemented.

[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 body 310 and its adjacent tank bodies, and can also control the exhaust assembly 330 to exhaust air from the interior of the drying tank body 310 and its adjacent tank bodies, thereby controlling the wind field inside the drying tank body 310 and its adjacent tank bodies and discharging reaction by-products. The controller can control the valve opening of the air inlet assembly 340 to introduce the corresponding process gas into the interior of the drying tank body 310; the controller can also control the opening and closing 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 valve opening of the water injection assembly 350 to inject water into the interior of the drying tank body 310.

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

[0072] The semiconductor process equipment 300 of the embodiment of the present application may be a Marangoni dryer. The embodiment of the present application does not limit the type of the semiconductor process equipment 300.

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

[0074] This embodiment further provides a machine-readable storage medium, which stores machine-executable instructions. When the machine-executable instructions are called and executed by a processor, the machine-executable instructions prompt the processor to implement the above-mentioned wafer drying method.

[0075] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described equipment and devices can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0076] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0077] In the description of the present invention, it should be noted that the terms "upper," "lower," and "inner," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present 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, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 an initial setting step, the drying tank body and its adjacent tank bodies are both set to a positive pressure wind field with upward delivery and downward exhaust, and the wind speed in the drying tank body is set to be greater than the wind speed in the adjacent tank bodies; a wafer water washing step, placing the wafer into the drying tank body and injecting water into the drying tank body until the wafer is immersed in water; In a drying setting step, dry gas is introduced into the drying tank body, and the wind speed difference between the drying tank body and the adjacent tank body 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, wherein: In the initial setting step, the wind speed difference between the drying tank body and the adjacent tank body is a first wind speed difference, and the ratio of the first wind speed difference to the wind speed in the drying tank body is 5-15%; In the drying setting step, the wind speed difference between the drying tank body and the adjacent tank body is a second wind speed difference, and the ratio of the second wind speed difference to the wind speed in the drying tank body is 15-30%.

3. The wafer drying method according to claim 1, wherein: The difference between the exhaust speed and the air supply speed of the drying trough is the drying exhaust difference, and the difference between the exhaust speed and the air supply speed of adjacent troughs is the adjacent exhaust difference. The initial setting 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 pumping difference to the air supply speed of the adjacent troughs is set to be equal to the ratio of the drying pumping difference to the air supply speed of the drying trough.

4. The wafer drying method according to claim 3, wherein: The drying setting step also includes: Increase the ratio of the drying pumping difference to the air supply speed of the drying trough body, and increase the ratio of the adjacent pumping differences to the air supply speed of the adjacent trough bodies.

5. The wafer drying method according to claim 4, wherein: The drying setting step comprises: Increase the air extraction speed of the drying trough body and reduce the air supply speed of the adjacent trough body.

6. The wafer drying method according to claim 4, wherein: In the initial setting step, the ratio of the drying pumping difference to the air supply speed of the drying trough is 5-15%, and the ratio of the adjacent pumping difference to the air supply speed of the adjacent trough is 5-15%; In the drying setting step, the ratio of the drying pumping difference to the air supply speed of the drying trough is 10-20%, and the ratio of the adjacent pumping differences to the air supply speed of the adjacent troughs is 10-20%.

7. The wafer drying method according to claim 1, wherein: The wind speed in the drying tank body is 0.3-0.4 m / s, and the wind speed in the adjacent tank body is 0.2-0.3 m / s.

8. The wafer drying method according to claim 1, wherein: The drying step includes: lifting the wafer until the wafer is completely out of the water; Alternatively, the drying step includes draining water from the drying tank until the wafers are completely exposed.

9. The wafer drying method according to claim 1, wherein: The drying gas includes isopropyl alcohol and nitrogen.

10. The wafer drying method according to claim 1, wherein: After the drying step, the method further comprises: In the purge step, the wafer is purged with an inert gas.

11. The wafer drying method according to any one of claims 1 to 10, characterized in that: After the purge step, the method further comprises: The wind field in the drying tank body and the wind field in the adjacent tank body are respectively restored to the wind field state in the initial setting step.

12. A semiconductor process equipment, comprising a drying tank, adjacent tanks, a wafer drive assembly, an air supply assembly, an air extraction 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, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the wafer drying method according to any one of claims 1 to 11 is implemented.

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