Packaging structure and preparation method thereof

Abstract

The invention discloses a packaging structure and a preparation method thereof, the packaging structure comprises a bonding area, a first wafer, a second wafer and a bonding structure, and the first wafer and the second wafer are bonded through the bonding structure in the bonding area; one side, facing the second wafer, of the first wafer is provided with at least one glue containing groove, and the glue containing groove penetrates through part of the first wafer; one side, facing the first wafer, of the second wafer is provided with a wafer electrode, and the bonding structure covers the wafer electrode and fills at least part of the glue containing groove; and along the thickness direction of the packaging structure, the glue accommodating groove is overlapped with the wafer electrode. According to the invention, the glue containing groove is arranged in the bonding area, and the glue containing groove can contain the bonding structure, so that the bonding structure is prevented from occupying the space of the wafer, more chips can be arranged on the wafer with the same size, and the utilization rate of the wafer is improved; and the bonding structure is arranged in the glue accommodating groove, so that the bonding area and the bonding strength of the bonding structure and the first wafer can be effectively increased, and the reliability of the packaging structure is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a packaging structure and a preparation method thereof. BACKGROUND

[0002] Compared with the traditional packaging process, the wafer level packaging process is to package the whole wafer (a plurality of chips are arranged in a matrix on each wafer) and then cut the wafer into chips.

[0003] In the prior art, the bonding strength of the adhesive layer is insufficient, and the adhesive layer may overflow, which has a reliability risk. In order to avoid the overflow problem, the cutting path between different chips is relatively wide, which affects the integration of the chips in the wafer and is not conducive to the setting requirement of high integration of the chips. SUMMARY

[0004] The present application provides a packaging structure and a preparation method thereof, which improves the wafer reliability and utilization.

[0005] The first aspect of the present application provides a packaging structure, comprising a bonding area;

[0006] The packaging structure further comprises a first wafer, a second wafer and a bonding structure, the first wafer and the second wafer are bonded by the bonding structure in the bonding area;

[0007] At least one adhesive groove is arranged on one side of the first wafer facing the second wafer, and the adhesive groove penetrates part of the first wafer; a wafer electrode is arranged on one side of the second wafer facing the first wafer, and the bonding structure covers the wafer electrode and fills at least part of the adhesive groove;

[0008] The adhesive groove and the wafer electrode overlap in the thickness direction of the packaging structure.

[0009] Optionally, the packaging structure further comprises a functional area, and the bonding area surrounds at least part of the functional area.

[0010] At least one fuse groove is arranged on one side of the second wafer facing the first wafer, and the fuse groove is located in the bonding area and on the side of the wafer electrode away from the functional area.

[0011] The fuse groove penetrates part of the second wafer and exposes part of the side wall of the second wafer.

[0012] The bonding structure fills at least part of the fuse groove and contacts and covers the side wall of the second wafer.

[0013] Optionally, a plurality of adhesive grooves are arranged on one side of the first wafer facing the second wafer.

[0014] Optionally, the packaging structure further comprises a functional region, and the bonding region surrounds at least part of the functional region.

[0015] In a direction from the functional region to the bonding region, the volumes of the plurality of glue accommodating grooves gradually increase.

[0016] Optionally, in a direction from the functional region to the bonding region, depths of the plurality of glue accommodating grooves gradually increase, and / or opening areas of the plurality of glue accommodating grooves gradually increase.

[0017] Optionally, in a direction from one side of the first wafer to the second wafer, the opening areas of the plurality of glue accommodating grooves gradually decrease.

[0018] Optionally, the packaging structure further comprises a functional region, and the bonding region surrounds at least part of the functional region.

[0019] The first wafer is provided with a cavity on a side facing the second wafer, and the cavity penetrates part of the first wafer; the second wafer is provided with a functional structure on a side facing the first wafer; and along a thickness direction of the packaging structure, the cavity and the functional structure overlap.

[0020] A second aspect of the present application provides a preparation method of a packaging structure, the packaging structure comprising a bonding region; the preparation method comprising:

[0021] providing a first wafer and preparing at least one glue accommodating groove in the first wafer at a position corresponding to the bonding region, the glue accommodating groove penetrating part of the first wafer;

[0022] providing a second wafer and preparing a wafer electrode in the second wafer at a position corresponding to the bonding region;

[0023] bonding the first wafer and the second wafer in the bonding region by using a bonding structure in a direction from the glue accommodating groove to the wafer electrode, the bonding structure covering the wafer electrode and filling at least part of the glue accommodating groove; and along a thickness direction of the packaging structure, the glue accommodating groove and the wafer electrode overlap.

[0024] Optionally, the packaging structure further comprises a functional region, and the bonding region surrounds at least part of the functional region.

[0025] bonding the first wafer and the second wafer in the bonding region by using a bonding structure, comprising:

[0026] preparing a fuse groove in the second wafer on a side of the second wafer, and on a side of the bonding region and the wafer electrode away from the functional region, the fuse groove penetrating part of the second wafer and exposing part of a side wall of the second wafer;

[0027] bonding the first wafer and the second wafer at the bonding region by a bonding structure, the bonding structure covering the wafer electrode and filling at least part of the adhesive groove and at least part of the fusing groove, the bonding structure contacting the sidewall of the second wafer.

[0028] Optionally, the packaging structure further comprises a functional region, the bonding region surrounding at least part of the functional region.

[0029] providing a first wafer and preparing at least one adhesive groove at a position of the first wafer corresponding to the bonding region, comprising:

[0030] providing a first wafer and preparing at least one adhesive groove at a position of the first wafer corresponding to the bonding region, and preparing a cavity at a position corresponding to the functional region; the cavity penetrating part of the first wafer.

[0031] providing a second wafer and preparing a wafer electrode at a position of the second wafer corresponding to the bonding region, comprising:

[0032] providing a second wafer and preparing a wafer electrode at a position of the second wafer corresponding to the bonding region, and preparing a functional structure at a position corresponding to the functional region.

[0033] The packaging structure provided by the embodiment of the present application reduces the risk of overflow of the bonding structure to the area outside the bonding region by arranging the adhesive groove in the bonding region and arranging the adhesive groove to accommodate the bonding structure, ensures that the bonding structure does not occupy more packaging space, ensures that more areas in the first wafer and the second wafer can be used as the functional region, and realizes the highly integrated arrangement of the wafer. The adhesive groove can also effectively increase the bonding area of the bonding structure and the first wafer by accommodating the bonding structure, thereby improving the bonding force and sealing strength of the bonding structure and the first wafer, and improving the reliability of the packaging structure. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 A packaging structure provided by the embodiment of the present application is shown in the figure;

[0035] Figure 2 Another packaging structure provided by the embodiment of the present application is shown in the figure;

[0036] Figure 3 Still another packaging structure provided by the embodiment of the present application is shown in the figure;

[0037] Figure 4 Yet another packaging structure provided by the embodiment of the present application is shown in the figure;

[0038] Figure 5 Still another packaging structure provided by the embodiment of the present application is shown in the figure;

[0039] Figure 6A flowchart of a preparation method of a packaging structure provided by an embodiment of the present application is shown in FIG. 1.

[0040] Figure 7 A flowchart of a preparation method of a packaging structure provided by an embodiment of the present application is shown in FIG. 1. Figure 6 A flowchart of a preparation method of a packaging structure provided by an embodiment of the present application is shown in FIG. 1.

[0041] Figure 8 A flowchart of a preparation method of a packaging structure provided by an embodiment of the present application is shown in FIG. 1.

[0042] Figure 9 A flowchart of a preparation method of a packaging structure provided by an embodiment of the present application is shown in FIG. 1. Figure 8 A flowchart of a preparation method of a packaging structure provided by an embodiment of the present application is shown in FIG. 1.

[0043] Figure 10 A flowchart of a preparation method of a packaging structure provided by an embodiment of the present application is shown in FIG. 1.

[0044] Figure 11 A flowchart of a preparation method of a packaging structure provided by an embodiment of the present application is shown in FIG. 1. Figure 10 A flowchart of a preparation method of a packaging structure provided by an embodiment of the present application is shown in FIG. 1. DETAILED DESCRIPTION

[0045] The present application will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are intended to be merely illustrative of the present application and not in limitation thereof. It should also be noted that, for the purpose of description, only the parts related to the present application are shown in the drawings rather than all the parts.

[0046] The bonding region can be understood as a region where the bonding structure is arranged when the first wafer and the second wafer are bonded. In the process of packaging and bonding the first wafer and the second wafer, it is inevitable that the bonding structure will overflow due to the extrusion of the first wafer and the second wafer. On the one hand, the overflowed bonding structure can contaminate the functional region in the packaging structure, and on the other hand, the region outside the bonding structure will occupy more space in the wafer, resulting in a decrease in the utilization rate of the wafer.

[0047] Based on this, Figure 1 A schematic diagram of a packaging structure provided by an embodiment of the present application is shown in FIG. 1. Figure 1 As shown in FIG. 1, the packaging structure includes a bonding region 10, and further includes a first wafer 20, a second wafer 30 and a bonding structure 40. The first wafer 20 and the second wafer 30 are bonded at the bonding region 10 through the bonding structure 40. The side of the first wafer 20 facing the second wafer 30 is provided with at least one glue groove 50, and the glue groove 50 penetrates part of the first wafer 20. The side of the second wafer 30 facing the first wafer 20 is provided with a wafer electrode 60, and the bonding structure 40 covers the wafer electrode 60 and fills at least part of the glue groove 50. In the thickness direction of the packaging structure, the glue groove 50 and the wafer electrode 60 overlap.

[0048] Specifically, as shown in Figure 1 embodiments of the present application adopt etching process to set at least one glue accommodating groove 50 on the side of the first wafer 20 facing the second wafer 30, and the glue accommodating groove 50 penetrates part of the first wafer 20, the depth of the glue accommodating groove 50 is greater than 1 μm and less than the thickness of the first wafer 20. The material of the first wafer 20 can be silicon, glass or other materials, and the depth of the glue accommodating groove 50 and the material of the first wafer 20 are not specifically limited in the embodiments of the present application. Further, the wafer electrode 60 is provided on the side of the second wafer 30 facing the first wafer 20, wherein the second wafer 30 can include wafer stack 301 and wafer body 302, and the wafer stack 301 can include piezoelectric layer and insulating layer. In the thickness direction of the packaging structure, the glue accommodating groove 50 overlaps with the wafer electrode 60, that is, the glue accommodating groove in the embodiments of the present application is correspondingly arranged with the wafer electrode, rather than being arranged at the cutting channel position of the transistor. When the first wafer 20 and the second wafer 30 are permanently bonded by the bonding structure 40, such as bonding glue, the bonding structure 40 covers the wafer electrode 60 and fills at least part of the glue accommodating groove 50. Because of the existence of the glue accommodating groove 50, the bonding structure 40 under pressure enters the glue accommodating groove 50 more than overflowing to the area outside the bonding area 10, that is, by setting the glue accommodating groove 50, the bonding structure 40 can be ensured to remain in the bonding area 10 more than overflowing to the area outside the bonding area, ensuring that the bonding structure 40 does not occupy more packaging structure space, ensuring that more areas in the first wafer 20 and the second wafer 30 can be used as functional areas, and realizing the high integration of the wafer.

[0049] Further, the glue accommodating groove 50 is arranged on the side of the first wafer 20 close to the second wafer 30, and after the bonding structure 40 enters the glue accommodating groove 50, the bonding area between the bonding structure 40 and the first wafer 20 can be increased, the bonding force between the first wafer 20 and the bonding structure 40 can be increased, and the packaging performance of the packaging structure can be ensured to be good.

[0050] In summary, the packaging structure provided by the embodiments of the present application sets the glue accommodating groove in the bonding area and uses the glue accommodating groove to accommodate the bonding structure, reduces the risk of the bonding structure overflowing to the area outside the bonding area, ensures that the bonding structure does not occupy more packaging space, ensures that more areas in the first wafer and the second wafer can be used as functional areas, and realizes the high integration of the wafer. The glue accommodating groove can also effectively increase the bonding area of the bonding structure and the first wafer by accommodating the bonding structure, thereby improving the bonding force and sealing strength of the bonding structure and the first wafer, and improving the reliability of the packaging structure.

[0051] Optionally, Figure 2 Another packaging structure provided by the embodiments of the present application is shown in Figure 2As shown, the packaging structure further comprises a functional area 70, and the bonding area 10 surrounds at least part of the functional area 70; the second wafer 30 is provided with at least one fusing groove 80 on the side facing the first wafer 20, the fusing groove 80 is located in the bonding area 10 and on the side of the wafer electrode 60 away from the functional area 70; the fusing groove 80 penetrates part of the second wafer 30 and exposes part of the sidewall of the second wafer 30; and the bonding structure 40 fills at least part of the fusing groove 80 and contacts the sidewall covering the second wafer 30.

[0052] Specifically, in the process of packaging the wafer, the wafer usually contains multiple chips, and each chip is arranged in a functional area 70, which is a region for realizing different electrical functions. Therefore, when packaging the wafer, it is necessary to avoid contamination of the functional area 70. Usually, after the wafer is packaged, the wafer is cut to form multiple single chips, and the pre-designed blank area on the wafer for cutting is a cutting path. In the embodiment of the present application, only the specific structure of a single chip is shown.

[0053] Further, the second wafer 30 is provided with at least one fusing groove 80 on the side facing the first wafer 20, the fusing groove 80 is located in the bonding area 10 and on the side of the wafer electrode 60 away from the functional area 70, as shown in Figure 2 The fusing groove 80 is located on the outside of the bonding area 10. Exemplarily, the fusing groove 80 can be formed by laser grooving, and its location can be the location of the cutting path. In the process of laser grooving, the fusing groove 80 can be arranged to penetrate part of the second wafer 30 and expose part of the sidewall of the second wafer 30, that is, the depth of the fusing groove 80 needs to be greater than the thickness of the wafer stack 301 and less than the overall thickness of the second wafer 30. Then, when the first wafer 20 and the second wafer 30 are bonded, the bonding structure 40 fills at least part of the fusing groove 80 and contacts the sidewall covering the second wafer 30, thereby effectively increasing the bonding area of the bonding structure 40 and the second wafer 30, and at the same time, the bonding structure 40 wrapping the sidewall of the second wafer 30 ensures the stability of the overall packaging structure.

[0054] The embodiment of the present application increases the bonding area of the bonding structure and the second wafer by arranging the fusing groove on one side of the second wafer and making the bonding structure fill at least part of the fusing groove and contact the sidewall covering the second wafer, improves the bonding strength, and at the same time, enhances the stability of the entire packaging structure. In addition, the fusing groove can accommodate the bonding structure, effectively avoiding the risk of overflow of the bonding structure, and further improving the utilization rate of the wafer.

[0055] Optionally, Figure 3 Another packaging structure provided by the embodiment of the present application is shown in FIG. 6, which is similar to the packaging structure shown in FIG. 5, and the difference is that the fusing groove 80 is arranged on the side of the second wafer 30 away from the first wafer 20. Figure 3As shown, the first wafer 20 is provided with a plurality of glue accommodating grooves 50 on the side facing the second wafer 30. With the increase of the number of the fuse grooves 50, not only more bonding structures 40 can be accommodated, but also the area outside the bonding area 10 is ensured not to be provided with the bonding structure 40, on the one hand, the functional area 70 is ensured not to be contaminated, on the other hand, the bonding structure 40 is avoided to overflow to the cutting path position, the cutting path width is reduced, the wafer utilization is improved, and on the other hand, the contact area of the bonding structure 40 and the first wafer 20 is also increased, so that the bonding is more stable.

[0056] In an optional embodiment, along the direction of the functional area 70 pointing to the bonding area 10, the volume of the plurality of glue accommodating grooves 50 gradually increases.

[0057] It can be understood that when the volume of the glue accommodating groove 50 gradually increases, the glue accommodating groove can accommodate more bonding structures 40, further reducing the risk of the bonding structure 40 overflowing outside the bonding area 10, fully ensuring that the functional area 70 is not contaminated, and fully avoiding the bonding structure 40 from overflowing to the cutting path position, reducing the cutting path width, and further improving the wafer utilization. At the same time, the bonding area of the bonding structure 40 and the first wafer 20 is also increased, thereby improving the bonding strength between the first wafer 20 and the bonding structure 40.

[0058] Further, along the direction of the functional area 70 pointing to the bonding area 10, the depth of the plurality of glue accommodating grooves 50 gradually increases, and / or the opening area of the plurality of glue accommodating grooves 50 gradually increases.

[0059] Specifically, along the direction of the functional area 70 pointing to the bonding area 10, the volume of the plurality of glue accommodating grooves 50 gradually increases, which can be realized by setting the depth of the plurality of glue accommodating grooves 50 gradually increasing along the direction of the functional area 70 pointing to the bonding area 10, and / or the opening area of the plurality of glue accommodating grooves 50 gradually increasing. Setting the depth of the plurality of glue accommodating grooves 50 gradually increasing, and / or the opening area of the plurality of glue accommodating grooves 50 gradually increasing can make the contact area of the bonding structure 40 and the first wafer 20 larger at a position farther away from the functional area 70, avoiding the occupation of the space of the wafer due to the overflow of the bonding structure 40 to the area outside the bonding area 10, ensuring the utilization of the wafer, further, since more bonding structures 40 can be accommodated at a position away from the functional area 70, the risk of contamination of the functional area 70 is effectively avoided, in addition, the bonding ability is the strongest at the edge of the first wafer 20, further enhancing the stability of the packaging structure.

[0060] Optionally, Figure 4 Another packaging structure provided by the embodiment of the present application is shown in FIG. 6. Figure 4 As shown, along the side of the first wafer 20 pointing to the second wafer 30, the opening area of the glue accommodating groove 50 gradually decreases.

[0061] Specifically, referring toFigure 4 The glue containing groove 50 can be in a reverse T-shaped structure, which makes the bonding structure 40 smaller and smaller in area on the side of the first wafer 20 pointing to the second wafer 30, that is, the closer to the inside of the first wafer 20, the larger the capacity of the bonding structure 40, which on the one hand increases the contact area between the bonding structure 40 and the inner wall of the glue containing groove 50, thereby increasing the bonding effect, and on the other hand, the side wall of the glue containing groove 50 plays a lifting effect, avoiding the bonding structure 40 from falling off the glue containing groove 50, and improving the bonding effect.

[0062] The embodiment of the present application changes the contact area of the bonding structure and the first wafer at different positions by changing the number, volume and shape of the glue containing groove, enhances the bonding strength of the two, makes the packaging structure more stable, and in addition, by setting the volume of the glue containing groove to be larger and larger away from the functional area, avoids the overflow of the bonding structure to the area outside the functional area, ensures the utilization rate of the wafer, and at the same time, can further avoid the risk of contamination of the functional area.

[0063] Optionally, Figure 5 Another packaging structure schematic diagram provided by the embodiment of the present application is shown in Figure 5 The first wafer 20 on the side facing the second wafer 30 is provided with a cavity 90, and the cavity 90 penetrates part of the first wafer 20; the second wafer 30 on the side facing the first wafer 20 is provided with a functional structure 701; along the thickness direction of the packaging structure, the cavity 90 and the functional structure 701 overlap.

[0064] Specifically, in order to avoid the functional structure 701 of the functional area 70 from being contaminated, an etching process is used to form a cavity 90 on the side of the first wafer 20 facing the second wafer 30, so that after packaging is completed, the functional structure 701 can be in the area where the cavity 90 is located, thereby forming protection for the functional structure 701, wherein the size of the cavity 90 needs to be larger than the size of the functional structure 701. It can be understood that the functional structure 701 here can be a chip.

[0065] Further, the cavity 90 and the glue containing groove 50 can be formed in the same etching process, thereby reducing the process steps, reducing the preparation difficulty of the containing groove 50 and the cavity 90, and improving the preparation efficiency of the containing groove 50 and the cavity 90.

[0066] In another optional embodiment, continuing to refer to Figure 5The packaging structure further comprises the interconnection metal 100, the under bump metal layer 110 and the bump 120. The second wafer 30 needs to be thinned before the interconnection metal 100 is prepared, and the thinning thickness is not limited in the embodiments of the present application. For example, the thinning can be performed by a grinding process. After the thinning, the interconnection metal 100 can be led out from the side of the second wafer 30 away from the first wafer 20 by a dry etching process and a hole-filling plating process, wherein the interconnection metal 100 is connected with the wafer electrode 60 at the side of the wafer electrode 60 close to the wafer stack 301, for leading out the electrical signal in the wafer electrode 60 to the outside of the chip, thereby realizing signal transmission.

[0067] Further, the under bump metal layer 110 is prepared at the side of the interconnection metal 100 away from the wafer electrode 60, for example, the under bump metal layer 110 can be prepared by a chemical plating process, wherein the under bump metal layer 110 can be nickel and gold. Then the bump 120 is prepared on the surface of the under bump metal layer 110, wherein the bump 120 is used for subsequent connection between chips, for example, the bump 120 can be formed by a printing or ball planting process, and the bump 120 can be a tin ball. Finally, the side of the first wafer 20 away from the second wafer 30 can be thinned, thereby obtaining the ultra-thin packaging structure as shown in Figure 5

[0068] The embodiments of the present application further protect the functional structure by setting the cavity on the first wafer. In addition, the interconnection metal can make the chips more easily connected, and the under bump metal layer and the bump on the surface of the interconnection metal can effectively prevent the oxidation of the interconnection metal, enhance the conductivity, and when the bump is prepared, the under bump metal layer can enhance the bonding rate of the interconnection metal and the bump, and improve the stability and reliability of the final product.

[0069] Figure 6 A flowchart of a preparation method of a packaging structure provided by the embodiments of the present application is shown in Figure 7 A corresponding preparation process flowchart of a packaging structure is shown in Figure 6 Figure 6 Figure 7 The preparation method of the packaging structure provided by the embodiments of the present application comprises:

[0070] S101, providing a first wafer and preparing at least one glue groove at the position corresponding to the bonding area of the first wafer, the glue groove penetrating part of the first wafer.

[0071] Specifically, refer to Figure 7 ​​​In step A1, at least one adhesive groove 50 is prepared at the position of the bonding area 10 corresponding to the first wafer 20, and the adhesive groove 50 penetrates a portion of the first wafer 20. For example, the first wafer 20 can be silicon, glass, etc., and at least one adhesive groove 50 can be formed by an etching process, wherein the depth of the adhesive groove 50 needs to be greater than 1μm but less than the thickness of the first wafer 20. The specific depth is not limited. When multiple adhesive grooves 50 are prepared, the spacing between each adhesive groove 50 is also not limited.

[0072] S102 , providing a second wafer and preparing wafer electrodes at positions corresponding to bonding regions of the second wafer.

[0073] Specifically, refer to Figure 7 In step B1, wafer electrodes 60 are formed on the second wafer 30 at locations corresponding to the bonding areas 10. For example, these electrodes can be formed using methods such as physical vapor deposition and electroplating. The second wafer 30 comprises a wafer stack 301 and a wafer body 302. The wafer stack 301 further comprises a piezoelectric layer and an insulating layer. Wafer electrodes 60 are used for signal transmission between different chips.

[0074] S103, with the adhesive groove facing the wafer electrode, use a bonding structure to bond the first wafer and the second wafer in the bonding area, the bonding structure covers the wafer electrode and fills at least part of the adhesive groove; along the thickness direction of the packaging structure, the adhesive groove overlaps with the wafer electrode.

[0075] Specifically, refer to Figure 7 In step C1, the glue groove 50 of the first wafer 20 is oriented toward the direction of the wafer electrode 60 of the second wafer 30, and the first wafer 20 and the second wafer 30 are bonded in the bonding area 10 using the bonding structure 40. It should be noted that the bonding position of the first wafer 20 and the second wafer 30 is the area where the glue groove 50 and the wafer electrode 60 are located, that is, along the thickness direction of the packaging structure, the glue groove 50 and the wafer electrode 60 overlap. By setting the glue groove 50 in the bonding area 10, the bonding structure 40 is avoided from overflowing to the area outside the bonding area 10, thereby improving the utilization rate of the wafer and the integration of the product. For example, the bonding structure 40 can be a bonding glue that can achieve permanent bonding between the first wafer 20 and the second wafer 30. The bonding structure 40 covers the wafer electrode 60 during the bonding process. At the same time, the bonding structure 40 is arranged in the adhesive groove 50, which increases the bonding area and bonding depth between the bonding structure 40 and the first wafer 20, making the packaging structure more stable.

[0076] In summary, the preparation method of the packaging structure provided by the embodiment of the application first prepares a glue accommodating groove at the bonding area position of the first wafer, then prepares a wafer electrode at the bonding area position of the second wafer, and overlaps the glue accommodating groove and the wafer electrode along the wafer thickness direction, so as to avoid the overflow of the bonding structure to the area outside the bonding area, and improve the utilization rate of the wafer and the integration of the product. Further, the first wafer and the second wafer are permanently bonded at the bonding area through the bonding structure, and the bonding structure is accommodated into the glue accommodating groove, so as to increase the bonding area and the bonding depth of the bonding structure and the first wafer, so that the packaging structure has stronger stability.

[0077] Optionally, Figure 8 The flowchart of another preparation method of a packaging structure provided by the embodiment of the application is shown in Figure 9 The preparation process flowchart of a corresponding packaging structure is shown in Figure 8 The preparation process flowchart of a corresponding packaging structure is shown in Figure 8 And Figure 9 On the basis of the above embodiment, bonding of the first wafer and the second wafer at the bonding area by the bonding structure is described in detail, as shown in Figure 8 And Figure 9 The packaging structure further includes a functional area 70, and the bonding area 10 surrounds at least part of the functional area 70. The preparation method of the packaging structure provided by the embodiment of the application includes the following steps.

[0078] S201, providing a first wafer and preparing at least one glue accommodating groove at the position corresponding to the bonding area of the first wafer, the glue accommodating groove penetrating part of the first wafer.

[0079] Specifically, refer to step A2 in Figure 9 .

[0080] S202, providing a second wafer and preparing a wafer electrode at the position corresponding to the bonding area of the second wafer.

[0081] Specifically, refer to step B2 in Figure 9 .

[0082] S203, preparing a fuse groove on one side of the second wafer and on the side of the bonding area and the wafer electrode away from the functional area, the fuse groove penetrating part of the second wafer and exposing part of the sidewall of the second wafer.

[0083] Specifically, refer to step C2 in Figure 9 , the fuse groove 80 is prepared on one side of the second wafer 30, wherein the fuse groove 80 is located on the side of the bonding area 10 and the wafer electrode 60 away from the functional area 70. Exemplarily, the fuse groove 80 can be formed in the form of laser grooving, and the fuse groove 80 penetrates part of the second wafer 30 and exposes part of the sidewall of the second wafer 30, the depth of which is greater than the wafer stack 301 but less than the overall thickness of the second wafer 30.

[0084] S204, using a bonding structure to bond the first wafer and the second wafer in the bonding area, the bonding structure covers the wafer electrodes and fills at least a portion of the adhesive containing groove and at least a portion of the fuse groove, and the bonding structure contacts and covers the side wall of the second wafer.

[0085] Specifically, refer to Figure 9 In step D2, the adhesive groove 50 of the first wafer 20 is oriented toward the wafer electrode 60 of the second wafer 30, and the first wafer 20 and the second wafer 30 are bonded together in the bonding area 10 using the bonding structure 40. The bonding structure 40 covers the wafer electrode 60 and fills at least a portion of the adhesive groove 50 and at least a portion of the fuse groove 80. The fuse groove 80 increases the bonding area between the bonding structure 40 and the second wafer 30. At the same time, the bonding structure 40 contacts and covers the sidewalls of the second wafer 30, enhancing the reliability of the packaging structure. The adhesive groove 50 and the fuse groove 80 are permanently connected by the bonding structure 40, and the entire packaging structure is sealed, further enhancing the reliability of the packaging structure.

[0086] By providing a fuse slot on one side of the second wafer and ensuring that the bonding structure fills at least a portion of the slot and contacts and covers the sidewall of the second wafer, this embodiment of the present invention increases the bonding area between the bonding structure and the second wafer, improving the bonding strength and enhancing the stability of the entire package structure. Furthermore, the fuse slot can accommodate the bonding structure, effectively avoiding the risk of overflow and further improving wafer utilization.

[0087] Optionally, Figure 10 A schematic flow chart of a method for preparing another packaging structure provided by an embodiment of the present invention is provided. Figure 11 for Figure 10 A schematic diagram of the preparation process flow of a corresponding packaging structure, Figure 10 and Figure 11 Based on the above embodiment, providing a first wafer and preparing at least one adhesive groove at a position corresponding to the bonding area of ​​the first wafer, and providing a second wafer and preparing wafer electrodes at a position corresponding to the bonding area of ​​the second wafer are described in detail, and a description of the steps of preparing bumps in the packaging structure is added, such as Figure 10 and Figure 11 As shown, the package structure further includes a functional area 70, and the bonding area 10 surrounds at least a portion of the functional area 70. The method for preparing the package structure provided in the embodiment of the present application includes:

[0088] S301, providing a first wafer and preparing at least one adhesive groove at a position corresponding to the bonding area of ​​the first wafer, and preparing a cavity at a position corresponding to the functional area; the cavity penetrates a portion of the first wafer.

[0089] Specifically, refer to Figure 11In step A3, to prevent contamination of the functional area 70, a cavity 90 is simultaneously formed at the corresponding location on the first wafer 20 while the adhesive reservoir 50 is being prepared using an etching process. This reduces the number of process steps and eases the manufacturing process. Cavity 90 extends through a portion of the first wafer 20, protecting the functional area 70 during the subsequent bonding of the first wafer 20 to the second wafer 30.

[0090] S302 , providing a second wafer and preparing wafer electrodes at positions corresponding to the bonding areas of the second wafer, and preparing functional structures at positions corresponding to the functional areas.

[0091] Specifically, refer to Figure 11 In step B3, a functional structure 701 is fabricated at the location corresponding to the functional area 70. Functional structure 701 enables chip signal processing and transmission, and determines the primary function of the chip. Therefore, during the fabrication of the packaging structure, contamination of functional structure 701 that could affect its normal function should be avoided. Wafer electrode 60 serves as the interface for signal exchange between functional structure 701 and external chips.

[0092] S303 , preparing a fuse groove on one side of the second wafer, in the bonding area and on the side of the wafer electrode away from the functional area, wherein the fuse groove penetrates a portion of the second wafer and exposes a portion of the sidewall of the second wafer.

[0093] Specifically, refer to Figure 11 Step C3 in .

[0094] S304, using a bonding structure to bond the first wafer and the second wafer in the bonding area, the bonding structure covers the wafer electrodes and fills at least a portion of the adhesive containing groove and at least a portion of the fuse groove, and the bonding structure contacts and covers the side wall of the second wafer.

[0095] Specifically, refer to Figure 11 Step D3 in .

[0096] S305 , after thinning the second wafer, lead the interconnect metal as a wafer electrode from a side of the second wafer away from the first wafer.

[0097] Specifically, refer to Figure 11 In step E3, the second wafer 30 can be thinned using a process such as grinding, with no specific limit on the thickness. To facilitate signal transmission between the wafer electrodes 60 and other chips, a metal interconnect 100 is formed on the side of the second wafer 30 away from the first wafer 20 through dry etching and via-filling electroplating. The metal interconnect 100 is connected to the wafer electrodes 60 on the side closest to the wafer stack 301.

[0098] S306, preparing an under-bump metallurgy layer and bumps on the interconnect metal surface.

[0099] Specifically, referring to step F3 in Figure 11 , a bump-under metal layer 110 is prepared on the side of the interconnection metal 100 away from the wafer electrode 60, which can be prepared by a chemical plating process, and the bump-under metal layer 110 can be nickel and gold. Then, a bump 120 is prepared on the surface of the bump-under metal layer 110, which is used for subsequent connection between chips, and the bump 120 can be formed by a printing or ball planting process, and the bump 120 can be a tin ball.

[0100] S307, thinning the first wafer.

[0101] Specifically, referring to step G3 in Figure 11 , the first wafer 20 of the packaging structure is finally thinned, which can be achieved by a grinding process, and a final ultra-thin packaging structure is formed.

[0102] The packaging structure preparation method provided by the embodiment of the present application can further protect the functional structure by setting a cavity on the first wafer, and can make the chips more easily connected by adding the interconnection metal, and can effectively prevent the oxidation of the interconnection metal by adding the bump-under metal layer and the bump on the surface of the interconnection metal, and can enhance the conductivity, and can enhance the combination rate of the interconnection metal and the bump when the bump is prepared, and can improve the stability and reliability of the final product.

[0103] Note that the above are only the preferred embodiments of the present application and the applied technical principles. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, re-adjustments and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A packaging structure, characterized in that: including a bonding area; The packaging structure further includes a first wafer, a second wafer and a bonding structure, wherein the first wafer and the second wafer are bonded at the bonding area through the bonding structure; At least one adhesive groove is provided on a side of the first wafer facing the second wafer, and the adhesive groove penetrates a portion of the first wafer; a wafer electrode is provided on a side of the second wafer facing the first wafer, and the bonding structure covers the wafer electrode and fills at least a portion of the adhesive groove; Along the thickness direction of the packaging structure, the adhesive containing groove overlaps with the wafer electrode.

2. The packaging structure according to claim 1, wherein: The packaging structure further includes a functional area, and the bonding area surrounds at least a portion of the functional area; At least one fuse slot is provided on a side of the second wafer facing the first wafer, and the fuse slot is located in the bonding area and on a side of the wafer electrode away from the functional area; The fuse groove penetrates a portion of the second wafer and exposes a portion of the sidewall of the second wafer; The bonding structure fills at least a portion of the fuse groove and contacts and covers a sidewall of the second wafer.

3. The packaging structure according to claim 1, wherein: A plurality of the adhesive containing grooves are provided on a side of the first wafer facing the second wafer.

4. The packaging structure according to claim 3, wherein: The packaging structure further includes a functional area, and the bonding area surrounds at least a portion of the functional area; Along the direction from the functional area to the bonding area, the volumes of the plurality of glue containing grooves gradually increase.

5. The packaging structure according to claim 4, wherein: Along the direction from the functional area to the bonding area, the depths of the plurality of adhesive containing grooves gradually increase, and / or the opening areas of the plurality of adhesive containing grooves gradually increase.

6. The packaging structure according to claim 1, wherein: Along a side of the first wafer pointing to the second wafer, the opening area of ​​the adhesive containing groove gradually decreases.

7. The packaging structure according to claim 1, wherein: The packaging structure further includes a functional area, and the bonding area surrounds at least a portion of the functional area; A cavity is provided on the side of the first wafer facing the second wafer, and the cavity penetrates a portion of the first wafer; a functional structure is provided on the side of the second wafer facing the first wafer; along the thickness direction of the packaging structure, the cavity and the functional structure overlap.

8. A method for preparing a packaging structure, characterized in that: The packaging structure includes a bonding area; and the preparation method includes: Providing a first wafer and preparing at least one adhesive groove at a position of the first wafer corresponding to the bonding area, wherein the adhesive groove partially penetrates the first wafer; Providing a second wafer and preparing wafer electrodes at positions of the second wafer corresponding to the bonding areas; With the glue groove facing the wafer electrode, the first wafer and the second wafer are bonded in the bonding area using a bonding structure, and the bonding structure covers the wafer electrode and fills at least part of the glue groove; along the thickness direction of the packaging structure, the glue groove overlaps with the wafer electrode.

9. The preparation method according to claim 8, characterized in that The packaging structure further includes a functional area, and the bonding area surrounds at least a portion of the functional area; Bonding the first wafer and the second wafer at the bonding area using a bonding structure, including: A fuse groove is formed on one side of the second wafer and at the bonding area and the side of the wafer electrode away from the functional area, wherein the fuse groove penetrates a portion of the second wafer and exposes a portion of the sidewall of the second wafer; The first wafer and the second wafer are bonded in the bonding area using a bonding structure, the bonding structure covers the wafer electrodes and fills at least part of the adhesive groove and at least part of the fuse groove, and the bonding structure contacts and covers the side wall of the second wafer.

10. The preparation method according to claim 8, characterized in that The packaging structure further includes a functional area, and the bonding area surrounds at least a portion of the functional area; Providing a first wafer and preparing at least one adhesive groove at a position of the first wafer corresponding to the bonding area, comprising: Providing a first wafer and preparing at least one adhesive groove at a position of the first wafer corresponding to the bonding area, and preparing a cavity at a position corresponding to the functional area; the cavity partially penetrates the first wafer; Providing a second wafer and preparing a wafer electrode at a position of the second wafer corresponding to the bonding area, comprising: A second wafer is provided and wafer electrodes are prepared at positions of the second wafer corresponding to the bonding areas, and functional structures are prepared at positions corresponding to the functional areas.

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