Wafer level packaging method and system

Abstract

The present invention discloses a wafer-level packaging method and system. The wafer-level packaging method includes: S1, providing a wafer, wherein the wafer includes a functional surface and a non-functional surface arranged relatively along its own axial direction; S2, uniformly coating an organic glue on the functional surface of the wafer; S3, placing the wafer obtained in S2 in a vacuum environment, adjusting the temperature of the vacuum environment, and baking the wafer in sections; firstly heating the temperature of the vacuum environment to a first temperature and maintaining it for a first time to remove the solvent in the organic glue, then heating the vacuum environment to a second temperature and maintaining it for a second time to solidify the organic glue, and then heating the vacuum environment to a third temperature and maintaining it for a third time, so that the organic glue is firmly fixed on the wafer. The present invention bakes the organic glue in sections when baking the organic glue, so that the solvent in the organic glue is volatilized, thereby improving the adhesion of the organic glue and better protecting the wafer.

Description

Technical Field

[0001] The invention relates to a wafer-level packaging method and system, and belongs to the technical field of integrated circuit packaging, optical communication and optoelectronic devices. Background Art

[0002] With the development of the information age, various types of high-precision optoelectronic devices have developed rapidly and are often used in the fields of semiconductor devices and optical communications. In the production process of wafer-level devices, hundreds to thousands or even tens of thousands of independent chips are generally produced on the wafer first, and then each independent chip is cut for subsequent production. However, during the chip cutting process, the cutting vibration and the impact force of the water jet will damage the device structure, causing the high-precision device to fail, which can easily cause chip damage and reduce the chip yield.

[0003] The existing technology will first encapsulate and protect the chip on the wafer with a protective glue, and then cut it to avoid chip damage and improve the chip production yield. Currently, photoresist is commonly used to encapsulate and protect the wafer, but photoresist is difficult to remove and requires long-term immersion in organic solvents to remove the photoresist. For some corrosion-resistant devices, photoresist can be used for encapsulation and protection, but many high-precision and high-sensitivity devices are not corrosion-resistant, and the device structure will be damaged during the removal of the photoresist. In addition, some liquid protective glues have poor adhesion, and the glue layer is easy to separate or fall off during the wafer cutting process, thereby affecting the protective effect of the protective glue during chip cutting. Summary of the invention

[0004] In view of the deficiencies in the prior art, an object of the present invention is to provide a wafer-level packaging method and system.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0006] The present invention provides a wafer-level packaging method, comprising the following steps:

[0007] S1. Providing a wafer, wherein the wafer includes functional surfaces and non-functional surfaces that are oppositely arranged along its own axial direction;

[0008] S2, uniformly coating the organic glue on the functional surface of the wafer;

[0009] S3, placing the wafer obtained in S2 in a vacuum environment, and adjusting the temperature of the vacuum environment to bake the wafer in sections;

[0010] First, the temperature of the vacuum environment is raised to a first temperature and maintained for a first time to remove the solvent in the organic glue. Then, the vacuum environment is raised to a second temperature and maintained for a second time to solidify the organic glue. Then, the vacuum environment is raised to a third temperature and maintained for a third time to make the organic glue firmly bonded to the wafer.

[0011] Preferably, in S2, the wafer is first pre-treated to remove impurities on the surface of the wafer.

[0012] Preferably, the pretreatment includes immersing the wafer in a cleaning solution and blowing it dry with a clean gas to remove impurities on the surface of the wafer.

[0013] Preferably, the cleaning liquid is alcohol, the wafer is immersed in the cleaning liquid for 10 minutes, and the cleaning gas is nitrogen.

[0014] Preferably, in S2, the wafer is horizontally placed on a glue coating platform, and a certain amount of organic glue is dripped on one side of the functional surface, and the organic glue is evenly spread on the wafer by moving the glue spreading mechanism along a selected direction.

[0015] Preferably, in S3, the first temperature is 50-70°C, the first time is 5-30 min, the second temperature is 80-100°C, the second time is 5-30 min, the third temperature is 100-130°C, and the third time is 5-30 min.

[0016] Preferably, after S3, the step further includes removing the organic glue remaining on the non-functional surface of the wafer by steam.

[0017] Preferably, the temperature of the steam is 130° C., and the time of the steam is 10 minutes.

[0018] Preferably, the wafer obtained in S3 is subjected to cutting verification, and the cutting verification step comprises:

[0019] S4, cutting the wafer;

[0020] S5, cleaning the wafer cut in S4 to remove the organic glue on the functional surface.

[0021] Preferably, the organic glue is a high-temperature water-soluble colloid structure.

[0022] Preferably, the coating thickness of the organic glue is 100-200 μm.

[0023] Preferably, in S5, the wafer is immersed in water at a temperature of 85° C. for 30 minutes to remove the organic glue on the functional surface.

[0024] The present invention also provides a wafer-level packaging system, which is applied to the above-mentioned wafer-level packaging method, and is characterized in that it comprises: a glue spreading device, the glue spreading device comprises a carrier and a glue spreading mechanism, the carrier is used to carry the wafer, the glue spreading mechanism is movably arranged on the carrier and moves along a selected direction to evenly coat the organic glue on the wafer;

[0025] A heating device, the heating device at least provides a vacuum environment and controls the temperature of the vacuum environment;

[0026] A conveying device is used at least to move the wafer from the carrier into the vacuum environment.

[0027] Preferably, the carrier includes a bearing portion and a limiting boss arranged along the circumference of the bearing portion, the bearing portion is used to bear the wafer, the limiting boss extends along the axial direction of the bearing portion, and the height of the limiting boss is not less than the sum of the thickness of the wafer and the thickness of the organic glue coating.

[0028] Preferably, the glue spreading device also includes a lifting mechanism, which is provided with a lifting part, which is movably arranged on the supporting part, and the lifting part can reciprocate along the axial direction of the supporting part to drive the wafer to move along its own axial direction between a first position and a second position. In the first position, the wafer as a whole protrudes from the limiting boss, and in the second position, the wafer is supported on the supporting part.

[0029] Preferably, the glue spreading mechanism is a roller structure, and the glue spreading mechanism can reciprocate along the radial direction of the wafer.

[0030] Preferably, the heating device is a vacuum oven.

[0031] Preferably, the conveying device comprises a robotic arm.

[0032] Preferably, it further comprises a hollow steam device, wherein the hollow steam device comprises a steam generating mechanism and a clamping mechanism, wherein the clamping mechanism is at least used for clamping the wafer, and the steam generating mechanism is at least used for inputting steam into the clamping mechanism.

[0033] Compared with the prior art, the advantages of the present invention include:

[0034] The present invention uses organic glue to coat the wafer and protect the device structure on the wafer, and can use pure water to remove the organic glue, thereby avoiding corrosion to the device structure of the wafer during the removal of the glue, thereby damaging the device structure. In addition, when baking the organic glue, the organic glue is baked in sections, which facilitates the volatilization of the solvent in the organic glue, thereby improving the adhesion of the organic glue and better protecting the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a cross-sectional structural diagram of a wafer coated with organic glue in one embodiment of the present invention;

[0036] Figure 2 It is a schematic cross-sectional view of the structure of a glue-splitting device in one embodiment of the present invention;

[0037] Figure 3 is a schematic cross-sectional view of a structure in which a top material portion is at a second position in an embodiment of the present invention;

[0038] Figure 4 yes Figure 3 A schematic cross-sectional view of the structure of the top material portion in the embodiment shown in the figure when the top material portion is in the first position;

[0039] Figure 5 It is a schematic cross-sectional view of the structure of a hollow steam device in use state in one embodiment of the present invention.

[0040] Description of reference numerals:

[0041] 100, wafer; 200, organic glue; 310, bearing part; 320, limiting boss; 330, glue spreading mechanism; 340, material lifting part; 410, steam generating mechanism; 411, inner cavity; 420, clamping mechanism; 421, supporting leg; 422, supporting baffle; 423, opening. DETAILED DESCRIPTION

[0042] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0044] In addition, in the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "horizontal", "vertical", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0045] In the description of this specification, the description with reference to the terms "one embodiment", "an embodiment", "the embodiment", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0046] The technical solution, its implementation process and principle will be further explained below in conjunction with the accompanying drawings.

[0047] As one aspect of the technical solution of the present invention, it relates to a wafer-level packaging method, which includes the following steps:

[0048] S1. Provide a wafer 100, wherein the wafer 100 includes a functional surface and a non-functional surface that are oppositely arranged along its own axial direction.

[0049] In this step, the wafer 100 used can be a wafer-level structure after being processed by a photolithography process, wherein a desired device structure is formed on one end face of the wafer 100 after photolithography and development, and this end face is the functional face of the wafer 100, while the end face of the wafer 100 facing away from the functional face has not been processed by photolithography, development and other processes, and serves as a non-functional face of the wafer 100.

[0050] S2, uniformly coating the organic glue 200 on the functional surface of the wafer 100;

[0051] In this step, if Figure 1 As shown, the wafer 100 is placed on a glue-spreading platform, and then the organic glue 200 is evenly coated on the functional surface of the wafer 100 so that it can cover the device structure on the functional surface, wherein the thickness of the coated organic glue 200 is much greater than the height of the device structure on the wafer 100, so that the organic glue 200 can be better wrapped, and the device structure on the wafer 100 can be better protected, which can effectively avoid the situation where the cutting vibration and the impact force of the water jet will damage the device structure when cutting the wafer 100, thereby effectively improving the yield of the wafer 100.

[0052] Specifically, in one embodiment, the wafer 100 is placed horizontally on the glue coating platform, and a certain amount of organic glue 200 is dripped on one side of the functional surface, and the organic glue 200 is evenly spread on the wafer 100 by moving the glue coating mechanism in a selected direction. When in use, the wafer 100 is fixed on the glue coating platform in a horizontal direction so that its functional surface is facing upward. When applying the organic glue 200, an appropriate amount of organic glue 200 is dripped on one side of the functional surface of the wafer 100. For example, the organic glue 200 is first dripped on the radial area of ​​the functional surface, and then the glue coating mechanism is in contact with the organic glue 200, and moves back and forth along the radial direction of the wafer 100, so that the organic glue 200 is evenly coated on the entire wafer 100.

[0053] By first dripping the organic glue 200 on one side of the functional surface, and then applying the organic glue 200 on the entire wafer 100 by reciprocatingly moving the glue spreading mechanism to push and compact the organic glue 200, the uniformity of the coating and the consistency of the thickness can be ensured. At the same time, the glue spreading mechanism reciprocates on the organic glue 200 to press the organic glue 200 against the surface of the wafer 100, further improving the adhesion between the organic glue 200 and the surface of the wafer 100, and improving the protection effect on the device structure.

[0054] The organic glue 200 is a high-temperature water-soluble colloid structure. The organic glue 200 does not dissolve in water at room temperature, but only dissolves in water at high temperature to ensure the stability of the package. The organic glue 200 can be selected as a hydrolyzed glue. In other embodiments, the organic glue 200 can also be a low-temperature decomposition glue or a heat-sensitive resin that does not react with organic solvents, thereby effectively avoiding damage to the wafer by organic solvents.

[0055] In addition, the coating thickness of the organic glue 200 is 100-200 μm.

[0056] Specifically, before the organic glue 200 is coated on the wafer 100 , the wafer 100 is pre-treated to remove impurities on the surface of the wafer 100 .

[0057] In this step, the wafer 100 to be packaged provided in step S1 is pre-treated to remove impurities or stains on the surface of the wafer 100, to ensure the cleanliness of the surface of the wafer 100, and to avoid impurities or stains being wrapped in the organic glue 200 when coating the organic glue 200, which are then easily reacted with the organic glue 200, thereby affecting the normal use of the device.

[0058] In one embodiment, the pretreatment includes soaking the wafer 100 in a cleaning solution and blowing it dry with a cleaning gas to remove impurities on the surface of the wafer 100. By soaking the wafer 100 in the cleaning solution, the impurities and stains on the surface of the wafer 100 are dissolved in the cleaning solution, thereby effectively avoiding direct contact with the device structure on the wafer 100 during the cleaning process, thereby easily damaging the device structure. According to the characteristics of the cleaning solution and the solubility of the impurities and stains, the wafer 100 is soaked for a corresponding time, then taken out of the cleaning solution, and the wafer 100 is air-dried with a cleaning gas to remove the cleaning solution remaining on the surface of the wafer 100, wherein the cleaning gas should not chemically react with the cleaning solution and the wafer 100.

[0059] Specifically, the cleaning liquid is alcohol, and the wafer 100 is soaked in the cleaning liquid for 10 minutes, and the cleaning gas is nitrogen. The wafer 100 is soaked in alcohol for 10 minutes to dissolve the impurities and stains on the surface of the wafer 100 in the alcohol. After the impurities and stains on the surface of the wafer 100 are removed, the wafer 100 is taken out of the alcohol. Due to the volatile nature of alcohol, the drying rate of the wafer 100 can be further improved. The wafer 100 is then air-dried with nitrogen, wherein nitrogen has a lower humidity and can effectively reduce the humidity in the air-drying environment. In addition, nitrogen can also exclude oxygen from the air-drying environment, thereby reducing the oxidation reaction on the surface of the wafer 100. Since nitrogen molecules are larger and less active, there is a lack of effective chemical reaction between nitrogen and the alcohol on the surface of the wafer 100 during the nitrogen air-drying process, so the drying speed is faster.

[0060] The process of nitrogen drying the wafer 100 is an existing conventional process, including:

[0061] Prepare a nitrogen source and a blow gun with a nitrogen blow nozzle. Before using nitrogen to blow dry, you need to connect the nitrogen source to the blow gun and ensure that the connection is tight to prevent gas leakage. Then, place the wafer 100 to be air-dried in a safe position. Among them, a stable bracket or support is selected to clamp and support the wafer 100 to prevent the wafer 100 from tipping over during the air-drying process. After that, turn on the nitrogen source and adjust the air pressure. The air pressure should be moderate, which can generate sufficient airflow without damaging the wafer 100. Aim the blow gun at the wafer 100 and direct the airflow to the desired position. During the drying process, a certain distance should be ensured between the blow gun and the wafer 100 to avoid excessive nitrogen blowing and splashing of the cleaning liquid. During the drying process, the angle and position of the blow gun can be adjusted in time to ensure that the airflow can evenly cover all surfaces of the wafer 100. This can speed up the drying speed and improve the drying effect. In addition, during the drying process, the wafer 100 can be rotated so that the airflow can better cover every corner of the surface of the wafer 100, which can reduce the drying time and ensure that the wafer 100 is completely dried. During the drying process, it is necessary to closely observe the changes of the wafer 100. Generally speaking, when there is no obvious liquid residue or water vapor on the surface of the wafer 100, it can be considered that the drying is completed.

[0062] S3. Place the wafer 100 obtained in S2 in a vacuum environment, and adjust the temperature of the vacuum environment to perform segmented baking on the wafer 100; first, raise the temperature of the vacuum environment to a first temperature and keep it for a first time to remove the solvent in the organic glue 200, then raise the temperature of the vacuum environment to a second temperature and keep it for a second time to solidify the organic glue 200, and then raise the temperature of the vacuum environment to a third temperature and keep it for a third time to firmly bond the organic glue 200 to the wafer 100.

[0063] In this step, the wafer 100 with the organic glue 200 coated on its surface is placed horizontally in a vacuum environment, and the temperature of the vacuum environment is adjusted in stages to bake the organic glue 200, so that the molten organic glue 200 is solidified on the surface of the wafer 100, thereby protecting the wafer 100. Since the organic glue 200 includes a solute and a solvent, and the adhesion of the organic glue 200 is related to the content of the solvent, the higher the solvent content, the lower the adhesion of the organic glue 200. When the organic glue 200 is baked, the solvent in the organic glue 200 needs to be volatilized and the organic glue 200 after the solvent is volatilized needs to be cured, so that the organic glue 200 is cured on the wafer 100, which plays a protective role on the device structure on the wafer 100. Therefore, during the baking process, the vacuum environment is first heated to a first temperature. At the first temperature, the solvent in the organic glue 200 reaches its boiling point and begins to volatilize. At the first temperature, the solute in the organic glue 200 does not reach the curing temperature and is still in a molten state. The solute of the organic glue 200 can fill the device structure. The organic glue 200 is placed in the gap between the structures so that it can better fit with the surface of the wafer 100, and the first temperature is maintained for a first time so that the solute in the organic glue 200 can be fully volatilized; then, the temperature of the vacuum environment is raised to a second temperature, at which the residual solute can continue to volatilize, and in addition, the solute in the organic glue 200 begins to be initially solidified from a molten state, and the second temperature is maintained for a second time to completely volatilize the remaining solute in the organic glue 200, and the solute in the organic glue 200 is pre-cured to reduce the fluidity of the solute so that it is initially fixed on the surface of the wafer 100; finally, the temperature of the vacuum environment is raised to a third temperature to further strengthen the organic glue 200 so that the organic glue 200 is completely cured on the surface of the wafer 100. When baking the organic glue 200, the solvent in the organic glue 200 can be fully volatilized by increasing the temperature in stages, thereby improving the adhesion of the organic glue 200 to prevent the organic glue 200 from falling off and becoming ineffective when the wafer 100 is subsequently cut.

[0064] Preferably, in S3, the first temperature is 50-70°C, the first time is 5-30 min, the second temperature is 80-100°C, the second time is 5-30 min, the third temperature is 100-130°C, and the third time is 5-30 min.

[0065] In addition, after step S4, the method further includes removing the residual organic glue 200 on the non-functional surface of the wafer 100 by steam. When the organic glue 200 is coated on the wafer 100, since the organic glue 200 has strong fluidity, the organic glue 200 will partially penetrate into the non-working surface of the wafer 100, that is, the back side of the wafer 100. The flow of the organic glue 200 on the back side of the wafer 100 is irregular. In the subsequent baking process, the organic glue 200 is also solidified into an irregular pattern on the back side of the wafer 100, thereby affecting the overall aesthetics and subsequent processes. Therefore, the organic glue 200 on the back side of the wafer 100 needs to be removed. In this embodiment, the organic glue 200 on the back of the wafer 100 is removed by steam, and the wafer 100 is placed on a hollow bracket, wherein the back of the wafer 100 is placed downward in the steam generating mechanism, and the steam generating mechanism can generate steam, and the steam then contacts and removes the organic glue 200 on the back of the wafer 100 through the hollow part on the bracket. The steam can be selected from PGMEA / acetone, etc., which can remove the organic glue. After the organic glue 200 on the back of the wafer 100 is removed, stop generating steam or move the wafer 100 out of the steam generating mechanism, and then blow dry the wafer 100. Specifically, the temperature of the steam can be selected to be 130°C, and the steam time is 10 minutes.

[0066] Performing cutting verification on the wafer obtained in S4, the cutting verification step includes S5, cutting the wafer 100;

[0067] S6. Clean the wafer 100 cut in step S5 to remove the organic glue 200 on the functional surface. Specifically, when the organic glue 200 is a hydrolyzed glue, soak the wafer 100 in water at a temperature of 85° C. for 30 minutes to remove the organic glue 200 on the functional surface. If the organic glue 200 is made of other materials, use a corresponding solvent to dissolve it.

[0068] In this step, the cutting process of the wafer 100 is a conventional standard process. The wafer 100 is first inspected, and the wafer 100 to be cut is inspected by an optical microscope and a probe tester to ensure that there are no cracks and defects on its surface. The wafer 100 is then glued to the cutting machine with special glue to ensure that it will not move or deform during the cutting process. After that, the wafer 100 is scribed, and the lines to be cut are marked on the surface of the wafer 100 by laser or mechanical means, and then the wafer 100 is cut, wherein the cutting method can be an internal separation cutting, and the wafer 100 is separated into individual chips by cutting along the predetermined lines with a high-speed rotating diamond saw blade. It can also be an external separation cutting, using a laser or mechanical method to draw a line with a depth of several microns on the surface of the wafer 100 and then forcefully break the wafer 100 to separate it into individual chips.

[0069] Through the above concept, the organic glue 200 is used to coat the wafer 100 and protect the device structure on the wafer 100. The organic glue 200 is a water-soluble glue, and pure water can be used to remove the organic glue 200 to avoid corrosion to the device structure of the wafer 100 during the removal of the glue, thereby damaging the device structure. In addition, by baking the organic glue 200 in sections, the solvent in the organic glue 200 is easily volatilized, thereby improving the adhesion of the organic glue 200, effectively avoiding the situation that the organic glue 200 will fall off the wafer 100 due to the cutting vibration and the impact force of the water knife when cutting the wafer 100, thereby easily damaging the device structure, and better protecting the wafer 100.

[0070] According to the above wafer-level packaging method, it can be used for the following applications:

[0071] Nano-scale columnar super-lens structure packaging: For high-performance double-sided super-lenses, the protection of the nano-scale columnar structure on the back has long been a problem for researchers. When using conventional photoresists for packaging, the photoresists have high viscosity, are difficult to remove, and have large capillary forces that cause structural collapse. Therefore, the above-mentioned wafer-level packaging method is used to encapsulate the nano-scale columnar super-lens structure, so that hydrolyzed glue can be used for packaging, which makes the capillary force between the colloids low and can be easily removed with clean water, thus completing the protection of the nano-scale structure.

[0072] It is worth noting that for nanoscale structures, the baking time should not be too long, 5-10 minutes. If the baking time is too long, the capillary force will become larger, causing the structure to collapse.

[0073] Large-size ultra-thin fragile device packaging (thin film): For large-size ultra-thin fragile device packaging (thin film), the surface has been coated, and the cleanliness of the film is extremely high. Organic cleaning agents can cause damage to the surface film. Therefore, such devices can be coated with hydrolyzed glue for protection to prevent damage to the device structure.

[0074] See also Figure 2-Figure 4 The present invention also provides a wafer-level packaging system, which is applied to the wafer-level packaging method, and includes a glue spreading device, which includes a carrier and a glue spreading mechanism 330, the carrier is used to carry the wafer 100, and the glue spreading mechanism 330 is movably arranged on the carrier and moves along a selected direction to evenly coat the organic glue 200 on the wafer 100; a heating device, the heating device at least provides a vacuum environment and controls the temperature of the vacuum environment; a conveying device, the conveying device is at least used to move the wafer 100 from the carrier to the vacuum environment.

[0075] In this embodiment, the glue spreading device includes a carrier and a glue spreading mechanism 330, wherein the carrier is placed horizontally. When in use, the functional surface of the wafer 100 is first fixed horizontally on the carrier with the functional surface facing upward, and the organic glue 200 is dripped on one side of the functional surface of the wafer 100. Then, the glue spreading mechanism 330 is used to reciprocate along the radial direction of the wafer 100 to coat the organic glue 200 on the entire wafer 100. Then, the wafer 100 coated with the organic glue 200 is transferred from the carrier to the vacuum environment of the heating device through the conveying device to bake the wafer 100 coated with the organic glue 200, so that the organic glue 200 is cured on the wafer 100. Among them, the heating device can control the temperature in the vacuum environment in sections, so that the organic glue 200 can be heated in sections, the volatilization effect of the solvent in the organic glue 200 is improved, and the adhesion of the organic glue 200 is provided.

[0076] The heating device may be a vacuum oven, and the conveying device may include a robotic arm.

[0077] Specifically, Figure 2 As shown, the carrier includes a bearing portion 310 and a limiting boss 320 arranged along the circumference of the bearing portion 310, the bearing portion 310 is used to bear the wafer 100, the limiting boss 320 extends along the axial direction of the bearing portion 310, and the height of the limiting boss 320 is not less than the sum of the thickness of the wafer 100 and the coating thickness of the organic glue 200. In this embodiment, the carrier includes a bearing portion 310 and a limiting boss 320, wherein the bearing portion 310 is a disc-shaped structure, the limiting boss 320 is arranged at the edge of the bearing portion 310 along the circumference of the bearing portion 310, and the limiting boss 320 extends upward along the axial direction of the bearing portion 310, so that the bearing portion 310 and the limiting boss 320 enclose a support space, the diameter of the support space is consistent with the diameter of the wafer 100, so that the wafer 100 can be better supported and the wafer 100 can be prevented from moving during the glue homogenization process. When in use, the wafer 100 is placed in the supporting space, and the back side of the wafer 100, that is, the non-functional surface of the wafer 100, is placed on the bearing part 310. The limiting boss 320 limits the wafer 100 in the horizontal direction, and the height of the limiting boss 320 can be equal to the sum of the thickness of the wafer 100 and the thickness of the organic glue 200 to be coated. The organic glue 200 is first dripped on one side of the functional area of ​​the wafer 100, and then the glue spreading mechanism 330 is used to move back and forth in the horizontal direction along the top of the limiting boss 320 to push the organic glue 200 to be evenly coated on the surface of the wafer 100 to ensure that the thickness of the organic glue 200 on the wafer 100 is consistent. Among them, in this embodiment, the glue spreading mechanism 330 is a roller structure, which reciprocates in the radial direction of the wafer 100 through the roller structure, thereby pushing the organic glue 200 to be coated on the wafer 100, and the organic glue 200 is compacted during the reciprocating movement. In this process, the limiting boss 320 can also limit the flow of the organic glue 200 to ensure the uniformity of the coating.

[0078] In addition, if Figure 3 , 4 As shown, the glue spreading device also includes a lifting mechanism, which is provided with a lifting part 340, which is movably arranged on the supporting part 310, and the lifting part 340 can reciprocate along the axial direction of the supporting part 310 to drive the wafer 100 to move along its own axial direction between a first position and a second position. In the first position, the wafer 100 protrudes as a whole from the limiting boss 320, and in the second position, the wafer 100 is supported on the supporting part 310.

[0079] After the organic glue 200 is coated on the wafer 100, the wafer 100 needs to be transferred to a heating device for baking. Due to the presence of the limiting boss 320, directly taking the wafer 100 may easily cause the wafer 100 to tilt. At this time, the organic glue 200 has not yet solidified, and the organic glue 200 is prone to tilting, resulting in uneven thickness of the organic glue 200 or even the organic glue 200 flowing out of the surface of the wafer 100. Therefore, it is necessary to first keep the wafer 100 horizontal and push out the limiting boss 320 in the vertical direction through a lifting mechanism, and then use a robotic arm to horizontally take the wafer 100 and move it to the heating device. In this embodiment, the lifting mechanism includes a lifting part 340, and the lifting part 340 can move up and down relative to the bearing part 310 along the axial direction of the bearing part 310, wherein the lifting part 340 can be a disc-shaped structure or a ring-shaped structure, and the lifting part 340 is coaxially arranged with the wafer 100. The material portion 340 can be movably embedded in the supporting portion 310. When pushing the wafer 100, the material push portion 340 abuts against the back side of the wafer 100 and pushes the wafer 100 to move to the first position along the vertical direction, so that the robot arm can take the wafer 100. After completing the transfer of the wafer 100, the material push portion 340 moves downward and is recovered in the supporting portion 310, wherein the top surface of the material push portion 340 is flush with or lower than the top surface of the supporting portion 310.

[0080] Preferably, a hollow steam device is further included, the hollow steam device includes a steam generating mechanism 410 and a clamping mechanism 420 , the clamping mechanism 420 is at least used for clamping the wafer 100 , and the steam generating mechanism 410 is at least used for inputting steam into the clamping mechanism 420 .

[0081] In this embodiment, if Figure 5As shown, the steam generating mechanism 410 includes an inner cavity 411, and the solution is placed in the inner cavity 411. The clamping mechanism 420 includes a support frame, and the support frame is composed of a plurality of support legs 421 and a support baffle 422. The plurality of support legs 421 extend in a vertical direction, and the plurality of support legs 421 are distributed along a circumference. The support baffle 422 is arranged in the middle of the circumference surrounded by the plurality of support legs 421. The support baffle 422 is respectively connected to the side walls of the plurality of support legs 421, so that the plurality of support legs 421 are connected together, the support baffle 422 is kept horizontal, and the support baffle 422 is provided with An opening 423 for steam to pass through is provided with a support portion capable of supporting the wafer at the periphery of the opening 423. When in use, the support legs 421 of the support frame are placed in the inner cavity 411, and the height of the support baffle 422 is greater than the height of the solution in the inner cavity 411. The wafer is then placed on the support baffle 422, wherein the edge of the wafer is supported on the support portion, and the back side of the wafer is exposed at the opening 423. The solution in the inner cavity 411 is then heated to generate steam, which contacts the back side of the wafer through the opening 423 of the support plate body to remove the organic glue on the back side of the wafer.

[0082] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A wafer-level packaging method, characterized in that: The following steps are involved: S1. Providing a wafer, wherein the wafer includes functional surfaces and non-functional surfaces that are oppositely arranged along its axial direction; S2, uniformly coating an organic adhesive on the functional surface of the wafer, specifically comprising: The wafer is placed horizontally on a glue coating platform, and a certain amount of organic glue is dripped on one side of the functional surface, and the organic glue is evenly spread on the wafer by moving along a selected direction through a glue spreading mechanism; the coating thickness is greater than the height of the device structure on the wafer, and the organic glue is a high-temperature water-soluble colloid structure; S3, placing the wafer obtained in S2 in a vacuum environment, adjusting the temperature of the vacuum environment, so as to perform segmented baking on the wafer, specifically comprising: First, the temperature of the vacuum environment is raised to a first temperature and maintained for a first time to remove the solvent in the organic glue and make the solute in the organic glue in a molten state to fill the gaps between the device structures so as to better fit with the wafer surface. Then, the vacuum environment is raised to a second temperature and maintained for a second time to solidify the organic glue, so that the solute therein is pre-solidified and preliminarily formed on the wafer surface. Then, the vacuum environment is raised to a third temperature and maintained for a third time to make the organic glue firm and completely solidified on the surface of the wafer. And, after completing S3, removing the organic glue remaining on the non-functional surface of the wafer by steam; then, performing cutting verification on the wafer, the cutting verification step includes: S4, cutting the wafer; S5, cleaning the wafer cut in S4 to remove the organic glue on the functional surface.

2. The wafer-level packaging method according to claim 1, characterized in that: In S2, the wafer is pre-processed to remove impurities on the surface of the wafer.

3. A wafer-level packaging method according to claim 2, characterized in that: The pretreatment includes immersing the wafer in a cleaning solution and blowing it dry with a cleaning gas to remove impurities on the surface of the wafer.

4. A wafer-level packaging method according to claim 3, characterized in that: The cleaning liquid is alcohol, the wafer is immersed in the cleaning liquid for 10 minutes, and the cleaning gas is nitrogen.

5. The wafer-level packaging method according to claim 1, characterized in that: In S3, the first temperature is 50-70°C, the first time is 5-30 min, the second temperature is 80-100°C, the second time is 5-30 min, the third temperature is 100-130°C, and the third time is 5-30 min.

6. The wafer-level packaging method according to claim 1, characterized in that: The temperature of the steam is 130° C., and the time of the steam is 10 minutes.

7. The wafer-level packaging method according to claim 1, characterized in that: In S5, the wafer is immersed in water at a temperature of 85° C. for 30 minutes to remove the organic glue on the functional surface.

8. The wafer-level packaging method according to claim 1, characterized in that: The coating thickness of the organic glue is 100-200 μm.

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