Drying method and drying device
By reducing the ultra-pure water temperature and optimizing the lifting and lifting speed during the slow lifting and drying of silicon wafers, the water marks and shaking problems on the surface of small-sized silicon wafers are solved, and the pass rate and drying adaptability of silicon wafers are improved.
Patent Information
- Application Number
- CN202411544464.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2024-12-27
AI Technical Summary
During the slow lifting and drying of silicon wafers, high-temperature processes cause local water marks on the surface of small-sized silicon wafers, affecting the quality of particles, and pauses during lifting and lifting handover will cause the silicon wafer to shake, reducing the manufacturing pass rate.
Using the drying method with ultrapure water temperature below 50℃, the silicon wafer is lifted upward under the liquid surface, and the silicon wafer is kept upward during the lifting and lifting handover process. The lifting speed is greater than the lifting speed. Optimize lift and lift speed ranges to avoid pauses and water marks, and use lift mechanisms to support and move the silicon wafer.
It effectively reduces the possibility of local water marks on the surface of the silicon wafer, improves the drying adaptability and manufacturing pass rate of silicon wafers of different sizes, and ensures the high cleanliness of the silicon wafers.
Smart Images
Figure CN119197056A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of chip manufacturing, and in particular to a drying method and a drying device. Background Art
[0002] With the vigorous development of emerging industries such as integrated circuits, artificial intelligence, big data, and autonomous driving, chip products are becoming more and more widely used.
[0003] The main steps in the manufacturing process of large-size silicon wafers for integrated circuits include crystal growth, crystal rod forming, silicon wafer forming, double-sided polishing of silicon wafers, and silicon wafer cleaning. Among them, the process capability of silicon wafer cleaning directly determines the surface cleanliness level of silicon wafers, and is also a key process step that determines the final quality of silicon wafers. The cleaning of silicon wafers specifically includes the cleaning process and the drying process. The cleaning process is mainly to clean the particles and metals on the surface of the silicon wafer, and the drying process is mainly to make the silicon wafers that have completed the cleaning process highly clean and dry on the surface. The drying process of large-size silicon wafers mainly adopts the slow pull-drying method. The slow pull-drying method is to place the large silicon wafer in a tank filled with ultrapure water, and use the silicon wafer pulling device to slowly pull the large silicon wafer out of the liquid surface to use the surface tension of the liquid to achieve the drying of the surface of the large silicon wafer.
[0004] At present, the slow pulling and drying process using ultrapure water as the medium solution generally adopts a high-temperature process, that is, the temperature of the ultrapure water is above 50°C. The large silicon wafer is continuously overflowed in the high-temperature ultrapure water bath for a period of time to make the large silicon wafer reach the same temperature as the ultrapure water. At this time, the large silicon wafer is slowly pulled out of the water through a pulling device to achieve the purpose of drying the silicon wafer surface. This process can meet the processing requirements of silicon wafers with relatively large particles (such as those with a size of more than 37nm), but the high-temperature slow-pulling process will cause water vapor to adhere to the surface of the silicon wafer during the processing of silicon wafers with relatively small particles, thereby forming local water marks on the surface of the silicon wafer, and causing the silicon wafer particles to fail to meet the detection requirements; in addition, the slow pulling process is that the pulling device on the water tank first runs to the lifting and pulling handover position directly above the silicon wafer, and then the lifting device in the water tank begins to slowly lift and rise; when it is lifted to the handover position, the lifting device begins to clamp and pull the silicon wafer completely away from the liquid surface. The silicon wafer is very easy to shake due to the pause in the lifting and pulling handover process, which leads to water marks and causes poor particles on the silicon wafer surface. Summary of the invention
[0005] The object of the present invention is to provide a drying method and a drying device for improving the adaptability of silicon wafer drying, avoiding the shaking of silicon wafers during the lifting and pulling handover process, reducing the possibility of local water marks on the surface of silicon wafers, and improving the qualified rate of silicon wafer manufacturing.
[0006] To achieve this object, the present invention adopts the following technical solutions:
[0007] Drying methods, including;
[0008] The temperature of ultrapure water is T, where T < 50°C;
[0009] The silicon wafer is located inside the ultrapure water and lifted upward;
[0010] When the partial structure of the silicon wafer is lifted out of the liquid surface, the handover between lifting and pulling is completed;
[0011] During the handover process, the silicon wafer is always lifted upward, and at the handover position between lifting and pulling, the pulling speed is greater than the lifting speed.
[0012] As an optional scheme for a drying method, the lifting speed range of the silicon wafer before it exits the liquid surface is V1mm / s~V2mm / s, and the lifting speed range after it exits the liquid surface is V1mm / s~V3mm / s, wherein V2>V3, and the average lifting speed of the silicon wafer before it exits the liquid surface is greater than the average lifting speed after it exits the liquid surface.
[0013] As an optional scheme for a drying method, the pulling speed range of the silicon wafer before it exits the liquid surface is V4mm / s to V5mm / s, and the pulling speed range after it exits the liquid surface is V4mm / s to V6mm / s, wherein V6>V5, and the average pulling speed of the silicon wafer after it exits the liquid surface is greater than the average pulling speed before it exits the liquid surface.
[0014] A drying device, wherein the drying device is based on the drying method described in any of the above schemes, and the drying device comprises a lifting mechanism, wherein the lifting mechanism is used to support the silicon wafer and drive the silicon wafer to move upward in a vertical direction.
[0015] As an optional solution for the drying device, the lifting mechanism includes a plurality of support members, and the plurality of support members can be arranged along the outer edge of the silicon wafer. The support members are provided with a fixing groove, and the outer edge of the silicon wafer can be arranged in the fixing groove.
[0016] As an optional solution of the drying device, the support member is a rod, and a plurality of the fixing grooves are sequentially spaced apart along the axial direction of the support member.
[0017] As an optional solution of the drying device, the cross-sectional shape of the fixed groove is an isosceles trapezoid, and the groove width of the fixed groove gradually decreases from the groove opening to the groove bottom.
[0018] As an optional solution of the drying device, the bottom width of the fixed groove is 1 / 2 of the groove opening width of the fixed groove.
[0019] As an optional solution of the drying device, the support member is further provided with two guiding inclined surfaces, the two guiding inclined surfaces respectively extend from the notches of the fixing groove in the direction away from the fixing groove, and the two guiding inclined surfaces extend in directions away from each other.
[0020] Beneficial effects:
[0021] In the first aspect of the present invention, the drying method can be used for small-sized silicon wafers. First, when the temperature of ultrapure water is T, where T is less than 50°C, the possibility of local water marks on the surface of the silicon wafer is reduced by optimizing the speed and handover position of lifting and pulling, thereby improving the qualified rate of silicon wafer manufacturing. Therefore, the drying method greatly ensures the adaptability of drying silicon wafers of different sizes. The silicon wafer is lifted upward from the liquid surface. After the partial structure of the silicon wafer is lifted to the liquid surface, the handover of lifting and pulling is completed. At the lifting and handover position, the pulling speed needs to be greater than the lifting speed to ensure that there is no pause during the lifting and pulling handover process, so as to avoid shaking of the silicon wafer, reduce the possibility of local water marks on the surface of the silicon wafer, and thus improve the qualified rate of silicon wafer manufacturing.
[0022] In the second aspect of the present invention, a drying device based on the drying method uses a lifting mechanism to control the lifting speed, while reducing the possibility of local water marks on the surface of the silicon wafer, thereby improving the qualified rate of silicon wafer manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 is a schematic structural diagram of a support member provided by an embodiment of the present invention;
[0024] Figure 2 yes Figure 1 A partial enlarged view at point A.
[0025] In the figure:
[0026] 1. Support member; 11. Fixing groove; 12. Guide slope. DETAILED DESCRIPTION
[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.
[0028] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0029] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.
[0030] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.
[0031] The first aspect of this embodiment relates to a drying method, which is used for the slow pulling and drying process of silicon wafers. Specifically, the temperature of ultrapure water is T, wherein T is less than 50°C; the silicon wafer is located inside the ultrapure water and lifted upward; when part of the structure of the silicon wafer is lifted out of the liquid surface, the handover between lifting and pulling is completed; during the handover process, the silicon wafer is always lifted upward, and at the handover position between lifting and pulling, the pulling speed is greater than the lifting speed.
[0032] Since the slow pulling method in the prior art mainly uses a high-temperature process, that is, the temperature of ultrapure water is above 50°C, this temperature is relatively suitable for drying large-sized silicon wafers, but for silicon wafers with relatively small particles (such as those with a size below 37nm), the water vapor adheres to the surface of the silicon wafer to form local water marks, causing the silicon wafer particles to not meet the requirements. Therefore, this drying method first sets the temperature of ultrapure water to T, where T is less than 50°C. Preferably, T ranges from 20°C to 35°C, but the lower ultrapure water temperature also affects the drying effect. Furthermore, by optimizing the speed and handover position of lifting and pulling to reduce the possibility of local water marks on the surface of the silicon wafer, the qualified rate of silicon wafer manufacturing is improved. Specifically, the silicon wafer is first lifted upward under the liquid surface. After part of the structure of the silicon wafer is lifted out of the liquid surface, the lifting and pulling handover must be completed. At the position of the lifting and pulling handover, the pulling speed needs to be greater than the lifting speed to ensure that the lifting and pulling handover process avoids pauses and causes the silicon wafer to shake, thereby further reducing the possibility of local water marks on the surface of the silicon wafer and improving the pass rate of silicon wafer manufacturing.
[0033] Optionally, the lifting speed range of the silicon wafer before it exits the liquid surface is V1mm / s~V2mm / s, and the lifting speed range of the silicon wafer after it exits the liquid surface is V1mm / s~V3mm / s, wherein V2>V3, and the average lifting speed of the silicon wafer before it exits the liquid surface is greater than the average lifting speed after it exits the liquid surface.
[0034] In this embodiment, V1=1mm / s, V2=16mm / s, V3=4mm / s, and the lifting speed of the silicon wafer before it leaves the liquid surface can be set according to the maximum value V2. Before leaving the liquid surface, the average lifting speed is greater than the average lifting speed after leaving the liquid surface, that is, before leaving the liquid surface, a larger lifting speed is used to ensure the drying effect, and after leaving the liquid surface, reducing the lifting speed is beneficial to the handover process of lifting and pulling the silicon wafer.
[0035] Optionally, the pulling speed range of the silicon wafer before it exits the liquid surface is V4mm / s~V5mm / s, and the pulling speed range of the silicon wafer after it exits the liquid surface is V4mm / s~V6mm / s, wherein V6>V5, and the average pulling speed after the silicon wafer exits the liquid surface is greater than the average pulling speed before it exits the liquid surface.
[0036] In this embodiment, V4=0.5mm / s, V5=5mm / s, V6=10mm / s. When the silicon wafer is below the liquid surface and is continuously lifted, the lifting mechanism has gradually moved upward to adapt to the handover. However, the speed is relatively small to facilitate the smooth lifting and pulling. When the silicon wafer is out of the liquid surface and the handover is completed, the lifting speed can be set according to the maximum value V6 to ensure the drying effect of the lifting process.
[0037] Please refer to the attached Figure 1 and attached Figure 2The second aspect of the present embodiment also relates to a drying device, which includes a lifting mechanism, which is used to support the silicon wafer and drive the silicon wafer to move upward in a vertical direction. The drying device also includes a pulling mechanism for connecting with the lifting mechanism to complete the subsequent pulling action to achieve a complete drying process.
[0038] Optionally, the lifting mechanism includes a plurality of support members 1 , and the plurality of support members 1 can be arranged along the outer edge of the silicon wafer. The support members 1 are provided with a fixing groove 11 around them, and the outer edge of the silicon wafer can be arranged in the fixing groove 11 .
[0039] The structure of the fixing groove 11 needs to adapt to the structure of the silicon wafer to ensure that the silicon wafer is reliably limited and stably fixed in the fixing groove 11 .
[0040] Furthermore, the support member 1 is a rod, and a plurality of fixing grooves 11 are sequentially arranged at intervals along the axial direction of the support member 1 .
[0041] The support member 1 is a cylindrical rod, and a plurality of fixing grooves 11 are arranged at intervals in the axial direction, so that a plurality of silicon wafers can be dried in the same ultrapure water tank by slowly pulling and drying in sequence, so as to improve the drying efficiency.
[0042] Optionally, the cross-sectional shape of the fixing groove 11 is an isosceles trapezoid, and the groove width of the fixing groove 11 gradually decreases from the groove opening to the groove bottom.
[0043] In this embodiment, the cross-sectional shape of the fixing groove 11 is an inverted isosceles trapezoid, and the open structure is suitable for the outer edge of the silicon chip to be smoothly embedded.
[0044] Furthermore, the bottom width of the fixing groove 11 is 1 / 2 of the groove opening width of the fixing groove 11 .
[0045] After optimization, the top opening width of the fixing groove 11 is 800 μm, and the bottom width of the fixing groove 11 is 400 μm.
[0046] Optionally, the support member 1 is further provided with two guiding inclined surfaces 12 , which extend from the notches of the fixing groove 11 in directions away from the fixing groove 11 , respectively, and the two guiding inclined surfaces 12 extend in directions away from each other.
[0047] In this embodiment, two guiding slopes 12 are further provided on the outer side of the groove opening of the fixing groove 11. The guiding slopes 12 can facilitate the smooth introduction of the silicon wafer into the guiding slopes 12, thereby improving the accuracy of installing the silicon wafer and facilitating the installation of the silicon wafer.
[0048] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. 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 claims of the present invention.
Claims
1. A drying method, characterized in that: include; The temperature of ultrapure water is T, where T < 50°C; The silicon wafer is located inside the ultrapure water and lifted upward; When the partial structure of the silicon wafer is lifted out of the liquid surface, the handover between lifting and pulling is completed; During the handover process, the silicon wafer is always lifted upward, and at the handover position between lifting and pulling, the pulling speed is greater than the lifting speed.
2. The drying method according to claim 1, characterized in that The lifting speed range of the silicon wafer before it exits the liquid surface is V1mm / s~V2mm / s, and the lifting speed range after it exits the liquid surface is V1mm / s~V3mm / s, wherein V2>V3, and the average lifting speed of the silicon wafer before it exits the liquid surface is greater than the average lifting speed after it exits the liquid surface.
3. The drying method according to claim 1, characterized in that The pulling speed range of the silicon wafer before it exits the liquid surface is V4mm / s~V5mm / s, and the pulling speed range after it exits the liquid surface is V4mm / s~V6mm / s, wherein V6>V5, and the average pulling speed of the silicon wafer after it exits the liquid surface is greater than the average pulling speed before it exits the liquid surface.
4. Drying device, characterized in that: The drying device is based on the drying method according to any one of claims 1 to 3, and the drying device comprises a lifting mechanism, and the lifting mechanism is used to support the silicon wafer and drive the silicon wafer to move upward in a vertical direction.
5. The drying device according to claim 4, characterized in that: The lifting mechanism comprises a plurality of support members (1), wherein the plurality of support members (1) can be arranged along the outer edge of the silicon wafer, and the support members (1) are provided with a fixing groove (11) around the support members (1), and the outer edge of the silicon wafer can be arranged in the fixing groove (11).
6. The drying device according to claim 5, characterized in that: The support member (1) is a rod member, and a plurality of fixing grooves (11) are sequentially arranged at intervals along the axial direction of the support member (1).
7. The drying device according to claim 5, characterized in that: The cross-sectional shape of the fixing groove (11) is an isosceles trapezoid, and the groove width of the fixing groove (11) gradually decreases from the groove opening to the groove bottom.
8. The drying device according to claim 5, characterized in that: The groove bottom width of the fixing groove (11) is 1 / 2 of the groove opening width of the fixing groove (11).
9. The drying device according to claim 5, characterized in that: The support member (1) is further provided with two guiding inclined surfaces (12), the two guiding inclined surfaces (12) respectively extending from the notches of the fixing groove (11) in a direction away from the fixing groove (11), and the two guiding inclined surfaces (12) extend in directions away from each other.