Vertical interconnection method and structure for substrate stacking and a structure thereof

Abstract

The present invention provides a vertical interconnection method for substrate stacking and a structure thereof. The vertical interconnection method involves following step: disposing a cured adhesive film on a first electrical substrate including multiple first pads and a prepreg adhesive film on a second electrical substrate including multiple second pads; forming multiple first openings aligning with the first pads in the cured adhesive film to obtain a first substrate unit via laser processing; forming multiple second openings aligning with the second pads in the prepreg adhesive film to obtain a second substrate unit via laser processing, wherein the diameters of the first openings are larger than the diameters of the second openings; forming multiple bumps made of conductive materials in the second openings; and pressing the first and second substrate units so that the bumps align with and fill the first openings, thereby forming a vertical interconnection structure.

Description

Technical Field

[0001] This invention relates to a method and structure for integrating electrical substrates, and more particularly to a method and structure for vertical interconnection of substrate stacking. Prior Technology

[0002] Vertical interconnect technology is often used in stacked electrical substrates (such as circuit boards, chips, or package structures) to electrically connect these stacked electrical substrates to each other, thereby enabling the configuration of more diverse and complex parts in a limited area, which helps to miniaturize and increase the density of electronic components.

[0003] Currently, vertical interconnect technologies are most commonly implemented in two ways. One method is Sequential Build-Up (SBU) technology, which is widely used in high-density printed circuit boards (PCBs) through high-density interconnect (HDI) processes. It mainly involves laser-forming blind vias, plated through-hole (PTH) plating, and lamination, achieving vertical interconnection by accumulating layers one by one. However, while this SBU technology is suitable for PCB stacks with fine lines or small dimensions, it is prone to misalignment, leading to localized electrical defects in the PCB stack and resulting in poor product reliability.

[0004] Another approach is conductive paste filling technology, which differs from the build-up layer technology in that it uses conductive paste filling instead of plated vias (PTH). This conductive paste filling technology can improve the thickness limitations of plating deposition and reduce the problem of poor electrical properties caused by insufficient conductive material filling. However, this conductive paste filling technology still has problems to overcome. For example, the bonding film used to form blind vias is brittle or soft, which can easily cause blind via misalignment during the process, affecting the alignment accuracy of the circuit board. In addition, voids or insufficient conductive paste filling may occur in the bonding film during bonding and / or lamination and baking, thereby reducing the reliability of vertical interconnects.

[0005] Therefore, improving alignment accuracy while ensuring the filling effect of the bonding between conductive materials and films to enhance product reliability and stability remains a pressing issue that needs to be addressed in the field of vertical interconnect technology. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide a vertical interconnection method for substrate stacking, which can prevent the film or conductive filler used for bonding electrical substrates from generating voids during the process, resulting in poor electrical properties or reliability of the product, and can also ensure that the two electrical substrates to be bonded have good alignment accuracy, thereby improving the process yield.

[0007] The present invention provides a vertical interconnection method for stacking substrates, used to vertically interconnect a first electrical substrate and a second electrical substrate, wherein the first electrical substrate has a first bonding surface and a plurality of first pads disposed on the first bonding surface, and the second electrical substrate has a second bonding surface and a plurality of second pads disposed on the second bonding surface. The vertical interconnection method for stacking substrates includes the following steps.

[0008] Step A involves forming a cured film on the first bonding surface, the cured film covering the first gaskets, forming a semi-cured film on the second bonding surface, and the semi-cured film covering the second gaskets.

[0009] Step B involves laser processing on the cured film to form multiple first openings at the positions of the first gaskets, so that the first gaskets are exposed from their respective first openings to form a first substrate unit. Similarly, laser processing is performed on the semi-cured film to form multiple second openings at the positions of the second gaskets, so that the second gaskets are exposed from their respective second openings to form a second substrate unit. The diameter of each first opening is larger than the diameter of each second opening.

[0010] Step C involves forming a plurality of bumps in the second openings using conductive material, and each of the bumps is electrically connected to a corresponding second pad.

[0011] Step D involves pressing the first substrate unit and the second substrate unit with the bumps together with the bumps facing the first openings, so that the bumps are aligned and filled into the first openings, and electrically connected to the corresponding first pads to form a vertical interconnect structure.

[0012] In this process, at least a portion of the structure of the semi-cured film fills the first openings and fills the gaps between the protrusions and the first openings.

[0013] In some embodiments, the cured film has a first film thickness, the semi-cured film has a second film thickness, and the second film thickness is greater than the first film thickness.

[0014] In some embodiments, the ratio of the thickness of the first film to the thickness of the second film is between 0.25:1 and 0.5:1.

[0015] In some embodiments, the first gaskets have a first gasket thickness, the second gaskets have a second gasket thickness, and the thickness of the first film is greater than the first gasket thickness, and the thickness of the second film is greater than or equal to the second gasket thickness.

[0016] In some embodiments, the cured film comprises fully cross-linked and cured plastic in stage C, and the semi-cured film comprises partially cross-linked plastic in stage B.

[0017] In some embodiments, before performing step B, a protective film is pre-formed on the second bonding surface of the semi-cured film, and a plurality of predetermined positions located on the second gaskets are defined on the protective film. Step B forms the second openings downward from the predetermined positions by laser processing, and the protective film is removed after step C. The height of the protective film is greater than or equal to the depth of the first openings, and the height of the bumps is greater than or equal to the sum of the depths of the first openings and the second openings.

[0018] Another object of the present invention is to provide a vertical interconnect structure.

[0019] The present invention provides a vertical interconnect structure for a substrate stacking architecture, comprising a first substrate unit, a second substrate unit, and a plurality of bumps.

[0020] The first substrate unit includes a first electrical substrate having a first bonding surface, a plurality of first pads disposed on the first bonding surface, and a cured film disposed on the first bonding surface and covering the first pads. The cured film has a plurality of first openings respectively opposite to the first pads, so that the first pads are exposed through the first openings.

[0021] The second substrate unit is electrically connected to the first substrate unit and includes a second electrical substrate having a second bonding surface, a plurality of second gaskets disposed on the second bonding surface, and a semi-cured film disposed on the second bonding surface and covering the second gaskets. The semi-cured film has a plurality of second openings respectively opposite to the second gaskets, so that the second gaskets are exposed from the second openings, and the diameter of each first opening is larger than the diameter of each second opening.

[0022] These bumps are made of conductive material and are disposed in the second openings and electrically connected to the corresponding second pads.

[0023] The first electrical substrate and the second electrical substrate are joined together with the bumps facing the first openings. The second openings are respectively located opposite the first openings. The bumps are aligned and filled into the first openings and electrically connected to the corresponding first gaskets. At least part of the semi-cured film is filled in the gap between the first openings and the bumps.

[0024] In some embodiments, the cured film has a first film thickness, the semi-cured film has a second film thickness, and the second film thickness is greater than the first film thickness.

[0025] In some embodiments, the ratio of the thickness of the first film to the thickness of the second film is between 0.25:1 and 0.5:1.

[0026] In some embodiments, the first gaskets have a first gasket thickness, the second gaskets have a second gasket thickness, and the thickness of the first film is greater than the first gasket thickness, and the thickness of the second film is greater than or equal to the second gasket thickness.

[0027] In some embodiments, the bumps have a bump height, and the bump height is greater than or equal to the sum of the depths of the first openings and the second openings.

[0028] The advantages of this invention are as follows: The vertical interconnect method for substrate stacking utilizes a partially fluid prepreg film disposed on a second electrical substrate to be bonded to the first electrical substrate. Through the dimensional design of the first and second openings, after the second electrical substrate is aligned and pressed onto the first electrical substrate, at least a portion of the prepreg film fills the first openings, densely filling them together with the bumps. This avoids voids around the bumps, thus improving the reliability of the vertical interconnect structure. Furthermore, the fully cured prepreg film ensures good alignment accuracy of the vertical interconnect structure. Moreover, the structural dimensional design of the prepreg film, the semiprepreg film, and the bumps reduces the probability of voids forming during the pressing process. Even if the openings of the prepreg film and the prepreg film slightly shift due to volume expansion and contraction during pressing, the alignment accuracy of the vertical interconnect structure can still be maintained. Simple Explanation of the Diagram

[0029] Figure 1 is a schematic diagram of a vertical interconnect structure according to an embodiment of the present invention; Figure 2 is a manufacturing flow chart of a vertical interconnect method according to an embodiment of the present invention; and Figures 3 to 5 are schematic diagrams of the process structure of a vertical interconnect method according to an embodiment of the present invention. Implementation

[0030] The technical content and effects of this invention will be clearly presented in conjunction with the accompanying drawings and the following detailed description of the embodiments. It should be noted that the drawings are only used to illustrate the relative positions of the elements and are not related to the actual dimensions of each element. Furthermore, those skilled in the art should understand that this invention can have various variations in multiple different embodiments, all of which do not depart from the essential scope of this invention. The descriptions and drawings are for illustrative purposes only and are not intended to constitute any limitation on this invention.

[0031] Referring to Figures 1 and 2, the vertical interconnection method for substrate stacking of the present invention is used to vertically interconnect a first electrical substrate 11 and a second electrical substrate 21 to obtain a vertical interconnection structure 100 as shown in Figure 1. This vertical interconnection structure 100 is used in a substrate stacking architecture, wherein the first electrical substrate 11 and the second electrical substrate 21 can be selected from wafers, circuit boards, packaging structures, or other electrical substrates with circuit structures. In this embodiment, a printed circuit board (PCB) is used as an example of the first electrical substrate 11 and the second electrical substrate 21 for illustration, but this is not a limitation.

[0032] The vertical interconnect structure 100 includes a first substrate unit 10, a second substrate unit 20, and a plurality of bumps 30. The first substrate unit 10 includes a first electrical substrate 11 having a first bonding surface 111, a plurality of first pads 13 disposed on the first bonding surface 111, and a curing film 12 disposed on the first bonding surface 111 and covering the first pads 13. The curing film 12 has a plurality of first openings 121 respectively facing the first pads 13, exposing the first pads 13 through the first openings 121. The first pads 13 are made of conductive material and are electrically connected to the internal circuit structure of the first electrical substrate 11, and can be electrically connected to the external circuit structure via the circuit structure.

[0033] The second substrate unit 20 is electrically connected to the first substrate unit 10 and includes the second electrical substrate 21 having a second bonding surface 211, a plurality of second pads 23 disposed on the second bonding surface 211, and a semi-cured film 22 disposed on the second bonding surface 211 and covering the second pads 23. The semi-cured film 22 has a plurality of second openings 221 respectively opposite to the second pads 23, so that the second pads 23 are exposed through the second openings 221, and the diameter of each first opening 121 is larger than the diameter of each second opening 221. The second pads 23 are made of conductive material and are electrically connected to the circuit structure inside the second electrical substrate 21, and can be electrically connected to the outside through the circuit structure.

[0034] The bumps 30 are made of conductive material, are disposed in the second openings 221 and are electrically connected to the corresponding second pads 23.

[0035] The first electrical substrate 11 and the second electrical substrate 21 are aligned and pressed together with the bumps 30 facing the first openings 121, and the second openings 221 are respectively aligned with the first openings 121. The bumps 30 are aligned and filled into the first openings 121 and electrically connected to the corresponding first pads 13, thereby realizing the vertical interconnection of the first substrate unit 10 and the second substrate unit 20. Since the diameter of the first openings 121 is larger than the diameter of the second openings 221, and the semi-cured film 22 has fluidity, it is advantageous for at least a portion of the structure of the semi-cured film 22 to fill the first openings 121, so that at least a portion of the semi-cured film 22 fills the gap between the first openings 121 and the bumps 30.

[0036] In this embodiment, the cured film 12 has a first film thickness T1, and the semi-cured film 22 has a second film thickness T2, wherein the second film thickness T2 is greater than the first film thickness T1. Therefore, when the semi-cured film 22 is bonded to the cured film 12, it can fully fill the first openings 121, avoiding gaps at the junction of the first substrate unit 10 and the second substrate unit 20, thereby preventing electrical defects or decreased reliability of the vertical interconnect structure 100. Preferably, the second film thickness T2 is at least twice the first film thickness T1. More preferably, the ratio of the first film thickness T1 to the second film thickness T2 is between 0.25:1 and 0.5:1.

[0037] In this embodiment, the first gaskets 13 have a first gasket thickness t1, the second gaskets 23 have a second gasket thickness t2, and the first film thickness T1 is greater than the first gasket thickness t1, and the second film thickness T2 is greater than or equal to the second gasket thickness t2, so as to ensure that the cured film 12 and the semi-cured film 22 can tightly cover the first gaskets 13 and the second gaskets 23, and prevent gaps from occurring between the film and the gaskets.

[0038] In this embodiment, the bumps 30 protrude from the second openings 221 and have a bump height h, and the bump height h is greater than or equal to the sum of the depths of the first openings 121 and the second openings 221. This can avoid the problem of poor electrical connection between some of the first pads 13 and the second pads 23 due to insufficient conductive material (i.e., the bumps).

[0039] It should be noted that in other embodiments, the thickness of the semi-cured film 22, the cured film 12, the first gaskets 13 and the second gaskets 23 may vary depending on actual needs, and are not limited to the examples mentioned above, as long as the diameter of the first openings 121 is greater than the diameter of the second openings 221.

[0040] The vertical interconnection method includes steps A through D.

[0041] Referring to Figures 2 and 3, step A involves forming the cured film 12 on the first bonding surface 111 of the first electrical substrate 11 and forming the semi-cured film 22 on the second bonding surface 211 of the second electrical substrate 21.

[0042] The thickness T2 of the second film is greater than the thickness T1 of the first film. Preferably, the ratio of the thickness T1 of the first film to the thickness T2 of the second film is between 0.25:1 and 0.5:1. The thickness T1 of the first film is greater than the thickness t1 of the first gasket, and the thickness T2 of the second film is greater than or equal to the thickness t2 of the second gasket.

[0043] The cured film 12 is selected from at least one of epoxy resin, polyimide (PI), acrylate, polyethylene terephthalate (PET), polyphenylene oxide (PPO), and polyphenylene ether (PPE), and the semi-cured film 22 is selected from at least one of epoxy resin, polyimide (PI), acrylate, polyethylene terephthalate (PET), polyphenylene oxide (PPO), and polyphenylene ether (PPE). Preferably, the cured film 12 and the semi-cured film 22 are selected from homologous plastic materials, which helps the cured film 12 and the semi-cured film 22 to undergo a cross-linking reaction during the pressing process, thereby improving the situation of voids at the joint surface. More preferably, the cured film 12 and the semi-cured film 22 are selected from the same type of plastic material.

[0044] In this embodiment, the cured film 12 is a fully cross-linked and cured plastic in the C-stage (fully cured stage), and includes polyoxyethylene (PPO). The semi-cured film 22 is a partially cross-linked plastic in the B-stage (partially cured stage), and also includes polyoxyethylene (PPO) as an example, but is not limited thereto.

[0045] In some embodiments, the cured film 12 and the semi-cured film 22 comprise polyoxyxylene (PPO) and a thermosetting resin. In other embodiments, the cured film 12 and the semi-cured film 22 comprise functionalized polyoxyxylene (PPO) having functional groups, such as hydroxyl, phenolic hydroxyl, amino, or epoxy groups.

[0046] In other embodiments, the semi-cured film 22 is fluid and comprises partially cross-linked epoxy resin and glass fiber.

[0047] Referring to Figures 1, 2, and 4, step B involves laser processing of the cured film 12 to form first openings 121 at the positions of the first gaskets 13, so that the first gaskets 13 are exposed from their respective first openings 121, forming the first substrate unit 10; and laser processing of the semi-cured film 22 to form second openings 221 at the positions of the second gaskets 23, so that the second gaskets 23 are exposed from their respective second openings 221, forming the second substrate unit 20, wherein the diameter of each first opening 121 is larger than the diameter of each second opening 221.

[0048] Step C involves forming a plurality of bumps 30 in the second openings 221 using a conductive material, and each of the bumps 30 is electrically connected to a corresponding second pad 23. The height h of each bump 30 is greater than or equal to the sum of the depths of the first openings 121 and the second openings 221. The bumps 30 are selected from at least one of a single-metal conductive material or a conductive organic material, but are not limited thereto.

[0049] More specifically, in this embodiment, before performing step B, a protective film (not shown) is pre-formed on the surface of the semi-cured film 22, and multiple preset positions corresponding to the second gaskets 23 are defined on the protective film. Then, step B is performed, and the second openings 221 are formed downwards from the predetermined positions via laser processing. Next, step C is performed, where a plurality of pre-formed bumps are formed on the second openings 221 using a conductive material (e.g., conductive paste), and cured according to the properties of the conductive material (e.g., heat curing or pressure curing) to cause a semi-curing reaction, forming the bumps 30. After step C, the protective film is removed. The height of the protective film is greater than or equal to the depth of the first openings 121, and the protective film is a PET film, but is not limited to this.

[0050] It should be noted that the material selection and detailed process steps (e.g., curing conditions) for forming these bumps 30 are known in the relevant fields and will not be elaborated upon here.

[0051] Referring to Figures 2 and 5, step D involves pressing the first substrate unit 10 and the second substrate unit 20, which is provided with the bumps 30, together with the bumps 30 facing the first openings 121, so that the bumps 30 are respectively aligned and filled into the first openings 121, and electrically connected with the corresponding first pads 13 to form the vertical interconnect structure 100.

[0052] Specifically, since the semi-cured film 12 is a B-stage plastic with fluidity and processability, and the thickness T2 of the second film is greater than the thickness T1 of the first film, at least a portion of the semi-cured film 22 will fill the first openings 121 during the lamination process, and fill the gaps S between the protrusions 30 and the first openings 121 (as shown in Figure 5), thus avoiding gaps caused by insufficient film content or volume expansion and contraction during the process. Furthermore, since the height h of the protrusions 30 is greater than or equal to the sum of the depths of the first openings 121 and the second openings 221, and the height of the protrusions 30 protruding from the surface of the semi-cured film 22 is not less than the depth of the first openings 121, it can prevent the partial electrical connection failure between the first pads 13 and the second pads 23 due to insufficient conductive material, or the increase in resistance of the vertical interconnect structure 100.

[0053] Furthermore, the cured film 12 disposed on the first electrical substrate 11 is a fully cross-linked and cured plastic in the C stage. Therefore, the volume expansion and contraction rate (i.e., coefficient of thermal expansion) of the cured film 12 is lower than that of the semi-cured film 22, making it less likely for the first openings 121 to shift during the manufacturing process. This helps to align the first electrical substrate 11 with the second electrical substrate 21. In addition, the design that the diameter of the first openings 121 is larger than the size of the second openings 221 can effectively reduce the problem of misalignment of the first openings 121 and the second openings 221 due to positional shift, thereby maintaining the alignment accuracy of the vertical interconnect structure 100.

[0054] In some embodiments, in step D, the first substrate unit 10 and the second substrate unit 20 are aligned and pressed together under a baking temperature between 180°C and 220°C and a pressure between 350 PSI and 450 PSI, so that the semi-cured film is further cured during the pressing and baking process of step 22, and cross-links with the cured film 12, avoiding gaps at the interface between the cured film 12 and the semi-cured film 22, which helps to improve the electrical properties and reliability of the vertical interconnect structure.

[0055] In this embodiment, in step D, the semi-cured film 22 and at least a portion of its structure filling the gaps S are fully cured. Since the height of the protrusions 30 extending into the first openings 121 is not less than the depth of the first openings 121, and the thickness of the semi-cured film 22 is at least twice the thickness of the cured film 12, even if at least a portion of the semi-cured film 22 filling the first openings 121 is cured, at least a portion of the structure of the semi-cured film 22 and the protrusions 30 can still fully fill the first openings 121 without creating gaps, thereby preventing local electrical defects in the vertical interconnect structure 100.

[0056] In summary, the vertical interconnect method for substrate stacking of the present invention, by providing a partially fluid prepreg film 22 on the second electrical substrate 12 to be bonded to the first electrical substrate 11, and by designing the diameter of the first openings 121 to be larger than the diameter of the second openings 221, ensures that after the second electrical substrate 21 is aligned and pressed onto the first electrical substrate 11, at least a portion of the prepreg film 22 and the bumps 30 densely fill the first openings 121, avoiding gaps around the bumps 30, thereby improving the reliability of the vertical interconnect structure 100. Furthermore, the size design of the first openings 121 and the second openings 221, combined with the fully cured prepreg film 12, gives the vertical interconnect structure 100 good alignment accuracy. Moreover, the structural size design of the prepreg film 12, the prepreg film 22, and the bumps 30 reduces the probability of gaps forming during the pressing process. Even if the openings of the cured film 12 and the cured film 22 shift slightly due to volume expansion and contraction during the pressing process, the alignment accuracy of the vertical interconnection structure 100 can still be maintained, thus achieving the purpose of the present invention.

[0057] Although the present invention has been disclosed with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0058] 100: Vertical interconnect structure 10: First substrate unit 11: First electrical substrate 111: First mating surface 12: Curing film 13: First gasket 121: First Opening 20: Second substrate unit 21: Second electrical substrate 211: Second mating surface 22: Semi-cured film 221: Second opening 23: Second gasket 30: Bump T1: First film thickness T2: Second film thickness t1: Thickness of the first gasket t2: Thickness of the second gasket h: bump height W1, W2: Caliber S: Gap A~D: Steps

Claims

1. A method for vertical interconnection of stacked substrates, used to vertically interconnect a first electrical substrate and a second electrical substrate, wherein, The first electrical substrate has a first bonding surface and a plurality of first pads disposed on the first bonding surface, and the second electrical substrate has a second bonding surface and a plurality of second pads disposed on the second bonding surface. The vertical interconnection method for stacking the substrates includes: Step A, forming a curable film on the first bonding surface and the curable film covering the first pads, forming a semi-curable film on the second bonding surface and the semi-curable film covering the second pads; Step B, forming a plurality of first openings at the positions of the first pads on the curable film using laser processing, so that the first pads are exposed from the corresponding first openings to form a first substrate unit, and forming a plurality of second openings at the positions of the second pads on the semi-curable film using laser processing, so that the second pads are exposed from the corresponding second openings to form a second substrate unit, wherein the diameter of each first opening is larger than the diameter of each second opening; Step C, forming a plurality of bumps in the second openings with conductive material, and electrically connecting the bumps to the corresponding second pads; and Step D, pressing the first substrate unit and the second substrate unit with the bumps together with the bumps facing the first openings, so that the bumps are aligned and filled into the first openings, so as to electrically connect with the corresponding first pads, forming a vertical interconnect structure; wherein at least a portion of the structure of the prepreg fills the first openings and fills the gaps between the bumps and the first openings.

2. The vertical interconnection method for substrate stacking as described in claim 1, wherein, The cured film has a first film thickness, and the semi-cured film has a second film thickness, wherein the second film thickness is greater than the first film thickness.

3. The vertical interconnection method for substrate stacking as described in claim 2, wherein, The ratio of the thickness of the first film to the thickness of the second film is between 0.25:1 and 0.5:

1.

4. The vertical interconnection method for substrate stacking as described in claim 2, wherein, The first gaskets have a first gasket thickness, the second gaskets have a second gasket thickness, and the thickness of the first film is greater than the first gasket thickness, and the thickness of the second film is greater than or equal to the second gasket thickness.

5. A vertical interconnection method for substrate stacking as described in claim 1, wherein, The cured film comprises fully cross-linked and cured plastic in stage C, and the semi-cured film comprises partially cross-linked plastic in stage B.

6. A vertical interconnection method for substrate stacking as described in claim 1, wherein, Before performing step B, a protective film is pre-formed on the second bonding surface of the semi-cured film, and a plurality of predetermined positions on the second gaskets are defined on the protective film. Step B forms the second openings downward from the predetermined positions by laser processing, and the protective film is removed after step C. The height of the protective film is greater than or equal to the depth of the first openings, and the height of the bumps is greater than or equal to the sum of the depths of the first openings and the second openings.

7. A vertical interconnect structure for a substrate stacking architecture, comprising: a first substrate unit including a first electrical substrate having a first bonding surface, a plurality of first pads disposed on the first bonding surface, and a cured film disposed on the first bonding surface and covering the first pads, wherein the cured film forms a plurality of first openings respectively opposite to the first pads, exposing the first pads through the first openings; a second substrate unit electrically connected to the first substrate unit, including a second electrical substrate having a second bonding surface, a plurality of second pads disposed on the second bonding surface, and a semi-cured film disposed on the second bonding surface and covering the second pads, the semi-cured film forming a plurality of second openings respectively opposite to the second pads, exposing the second pads through the second openings, wherein the diameter of each first opening is larger than the diameter of each second opening; and a plurality of bumps made of conductive material, disposed on the second openings and electrically connected to corresponding second pads; wherein... The first electrical substrate and the second electrical substrate are joined together with the bumps facing the first openings, the second openings are respectively located opposite the first openings, the bumps are aligned and filled into the first openings and electrically connected to the corresponding first gaskets, and at least part of the semi-cured film is filled in the gap between the first openings and the bumps.

8. The vertical interconnect structure as described in claim 7, wherein, The cured film has a first film thickness, the semi-cured film has a second film thickness, and the second film thickness is greater than the first film thickness. The first gaskets have a first gasket thickness, the second gaskets have a second gasket thickness, and the first film thickness is greater than the first gasket thickness, and the second film thickness is greater than or equal to the second gasket thickness.

9. The vertical interconnect structure as described in claim 8, wherein, The ratio of the thickness of the first film to the thickness of the second film is between 0.25:1 and 0.5:

1.

10. The vertical interconnect structure as described in claim 7, wherein, The bumps have a bump height that is greater than or equal to the sum of the depths of the first openings and the second openings.

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