Filling method of substrate through hole, substrate and electronic equipment

Abstract

The invention provides a substrate through hole filling method, a substrate and electronic equipment, relates to the technical field of electronic components, and can improve the efficiency of filling a conductive material in a through hole. The method comprises the following steps: providing a substrate; a through hole penetrating through the substrate is formed in the substrate; immersing the substrate into the dipping solution; the through hole is fully soaked in the soaking solution, the soaking solution contains M ions, the ion concentration of the M ions is a first concentration, and the M ions are at least one metal ion; the substrate is taken out of the dipping solution and dried, so that a solid-state collection layer is formed on the inner wall of the through hole, and the solid-state collection layer contains M salt; placing the substrate into an electroplating solution for electroplating; the through hole is fully soaked in the electroplating solution, the electroplating solution contains M ions, the concentration of the M ions in the electroplating solution is second concentration, and the second concentration is larger than the first concentration.

Description

Technical Field

[0001] The present application relates to the technical field of electronic components, and in particular to a method for filling a through-hole of a substrate, a substrate, and an electronic device. Background Art

[0002] A through-hole can be provided on a substrate, and a conductive material can be filled in the through-hole subsequently so that the through-hole can conduct electricity.

[0003] In the existing solutions, a seed layer needs to be formed in the through-hole first. However, in some cases, the seed layer may not be generated in some parts of the through-hole, resulting in poor subsequent electroplating effect, and further reducing the efficiency of filling the conductive material in the through-hole. Summary of the Invention

[0004] The present application provides a method for filling a through-hole of a substrate, a substrate, and an electronic device, which can improve the efficiency of filling a conductive material in the through-hole.

[0005] To achieve the above object, the present application adopts the following technical solutions:

[0006] In a first aspect, a method for filling a through-hole of a substrate is provided. The filling method includes: providing a substrate; a through-hole penetrating the substrate is provided on the substrate; immersing the substrate in an impregnation solution; the impregnation solution fills the through-hole, the impregnation solution contains M ions, the ionic concentration of the M ions is a first concentration, and the M ions are at least one kind of metal ions; taking out the substrate from the impregnation solution and drying the substrate so that a solid aggregation layer is formed on the inner wall of the through-hole, and the solid aggregation layer contains M salt; putting the substrate into an electroplating solution for electroplating; the electroplating solution fills the through-hole, the electroplating solution contains M ions, and the concentration of the M ions in the electroplating solution is a second concentration, and the first concentration is greater than the second concentration.

[0007] Compared with the existing solution of first generating a seed layer in a through-hole and then filling the through-hole, the solution of the present application provides a substrate provided with through-holes. Subsequently, the substrate is immersed in an impregnation solution to fill the through-holes, and then the substrate is taken out of the impregnation solution and dried. Then, the substrate is placed in an electroplating solution that fills the through-holes for electroplating. Since the impregnation solution contains M ions that are metal ions, the ionic concentration of M ions is a first concentration. After drying the substrate, a solid accumulation layer containing M salt is formed on the inner wall of the through-holes on the substrate. The electroplating solution contains M ions, and the concentration of M ions in the electroplating solution is a second concentration. Since the first concentration is greater than the second concentration, the concentration of M ions in the solid accumulation layer is higher than that of M ions in the electroplating solution. When electroplating with the electroplating solution, the solid accumulation layer in the through-hole will be preferentially selected for reduction. At this time, the M salt in the through-hole can serve as an autocatalytic center to initiate the electroplating reaction, causing the M ions in the electroplating solution to deposit into the through-hole. The surface of the substrate outside the through-hole inhibits the deposition of M ions due to the low concentration of M salt, and thus more M metal accumulates in the through-hole. Therefore, in this embodiment, filling of the through-hole can be achieved without forming a seed layer in the through-hole. In addition, the hole filling method provided in this embodiment does not form an extra metal layer on the surface of the substrate, reducing waste of resources.

[0008] In combination with the first aspect, in some embodiments of the first aspect, the impregnation solution is a surface tension solution with a surface tension ≥ 30 N / m.

[0009] In this way, the capillary effect can be utilized to enhance the retention ability of the impregnation solution in the through-hole and improve the coverage rate of the impregnation solution on the through-hole.

[0010] In combination with the first aspect, in some embodiments of the first aspect, the impregnation solution is a saturated solution of M ions, and the electroplating solution is an unsaturated solution of M ions.

[0011] In combination with the first aspect, in some embodiments of the first aspect, before placing the substrate in the electroplating solution, the substrate is immersed in the impregnation solution again and dried again.

[0012] By immersing the substrate in the impregnation solution and drying it multiple times, the uniformity of the distribution of M salt on the hole wall of the through-hole can be improved.

[0013] In combination with the first aspect, in some embodiments of the first aspect, the ratio of the first concentration to the second concentration is greater than or equal to 8:1.

[0014] In combination with the first aspect, in some embodiments of the first aspect, the surface tension solution further contains a surfactant, and the surfactant includes polyethylene glycol.

[0015] In this way, the surface tension of the impregnation solution can be increased.

[0016] In combination with the first aspect, in certain embodiments of the first aspect, the mass percentage of polyethylene glycol is 0.01 wt% - 0.1 wt%.

[0017] In combination with the first aspect, in certain embodiments of the first aspect, the M ion is a copper ion, and the impregnation solution includes CuSO₄·5H₂O.

[0018] In combination with the first aspect, in certain embodiments of the first aspect, the first concentration is 0.3 mol / L - 1.2 mol / L.

[0019] In combination with the first aspect, in certain embodiments of the first aspect, the thickness range of the solid-state accumulation layer is 50 nm - 200 nm.

[0020] In combination with the first aspect, in certain embodiments of the first aspect, immersing the substrate in the impregnation solution includes: placing the substrate in the impregnation solution under a preset vacuum degree and maintaining for a preset duration.

[0021] In a second aspect, a substrate is provided, which is fabricated by using the filling method provided in the first aspect and any one of its embodiments.

[0022] In a third aspect, an electronic device is provided, which includes the substrate provided in the second aspect.

[0023] Among them, the technical effects brought by any one of the embodiments in the second aspect to the third aspect can refer to the technical effects brought by different embodiments in the first aspect above, and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic flow chart of a filling method for through-holes of a substrate provided in an embodiment of the present application;

[0025] Figure 2 It is a schematic diagram of the process of filling through-holes of a substrate provided in another embodiment of the present application;

[0026] Figure 3 It is a schematic diagram of an electroplating scenario for filling through-holes of a substrate provided in an embodiment of the present application;

[0027] Figure 4 It is a schematic diagram of the process of filling through-holes of another substrate provided in the present application.

[0028] REFERENCE SIGNS:

[0029] Substrate - 10, Through-hole - 101, Impregnation Solution - 20, Solid-state Accumulation Layer - 30, Electroplating Solution - 40, Power Supply - 50, Positive Electrode - 60, Negative Electrode - 70. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In the description of the present application, unless otherwise specified, "a plurality" means two or more than two. "At least one of the following" or its similar expressions refer to any combination of these items, including any combination of single item or plural items. For example, at least one of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, c can be single or plural.

[0031] In addition, for the convenience of clearly describing the technical solutions of the embodiments of the present application, in the embodiments of the present application, terms such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects. Those skilled in the art can understand that terms such as "first" and "second" do not limit the quantity and execution order, and "first", "second", etc. do not necessarily mean different.

[0032] Meanwhile, in the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplary" or "for example" aims to present relevant concepts in a specific way for easy understanding.

[0033] It can be understood that the "embodiments" mentioned throughout the specification mean that specific features, structures or characteristics related to the embodiments are included in at least one embodiment of the present application. Therefore, the embodiments throughout the specification do not necessarily refer to the same embodiments. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It can be understood that in various embodiments of the present application, the magnitude of the sequence numbers of the processes does not mean the sequence of execution order, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0034] It can be understood that some optional features in the embodiments of the present application, in some scenarios, can be implemented independently without relying on other features, such as the current solution it is based on, to solve the corresponding technical problems and achieve the corresponding effects. In some scenarios, they can also be combined with other features according to requirements. Correspondingly, the devices given in the embodiments of the present application can also implement these features or functions accordingly, which will not be elaborated here.

[0035] In this application, unless otherwise specified, the same or similar parts between the various embodiments can refer to each other. In the various embodiments in this application, and the various implementation methods in each embodiment, if there is no special description and logical conflict, the terms and / or descriptions between different embodiments and the various implementation methods in each embodiment are consistent and can be referenced to each other. The technical features in different embodiments and the various implementation methods in each embodiment can be combined to form new embodiments, implementation methods, implementation methods, or implementation methods according to their inherent logical relationships. The following implementation methods of this application do not constitute a limitation on the scope of protection of this application.

[0036] The substrate may be provided with through holes, and conductive materials may be subsequently filled in the through holes to enable the through holes to conduct electricity.

[0037] The existing solutions require first generating a seed layer in the through hole and then depositing a conductive material on the seed layer. However, in some cases, for example, when the through hole has a high aspect ratio (e.g., 5:1-30:1), the seed layer may not be generated in certain parts of the through hole, resulting in discontinuity of the conductive layer subsequently deposited on the through hole wall, thereby reducing the efficiency of filling the conductive material in the through hole.

[0038] In order to solve the above problems, the present application provides a method for filling a through hole of a substrate. Figure 1 A schematic diagram of a method for filling a substrate through hole according to an embodiment of the present application is shown in FIG. Figure 1 As shown, the method for filling a substrate through hole provided in the present application may include the following steps:

[0039] Step S101 , providing a substrate 10 , wherein the substrate 10 is provided with a through hole 101 penetrating the substrate 10 .

[0040] It should be noted that the material of the substrate 10 can be glass, ceramic, etc., and this application does not impose any specific limitation on this.

[0041] The number of the through holes 101 on the substrate 10 may be one or more, and this application does not impose any specific limitation on this.

[0042] The aspect ratio of the through hole 101 is 5:1-30:1. For example, the aspect ratio of the through hole 101 may be 5:1, 10:1, 15:1, 20:1, 25:1, or 30:1, and the present application does not impose any specific limitation on this.

[0043] Step S102 , immersing the substrate 10 into an immersion solution 20 , the immersion solution 20 fills the through hole 101 , the immersion solution 20 contains M ions, the ion concentration of the M ions is a first concentration, and the M ions are at least one metal ion.

[0044] The impregnation solution 20 is a saturated solution of M ions.

[0045] The M ion can be a silver ion or a copper ion. Of course, the M ion can also include other metal ions, and this application does not make specific restrictions on this. Preferably, the M ion is a copper ion, and the impregnation solution 20 can include CuSO₄·5H₂O.

[0046] The impregnation solution 20 can be a surface tension solution, and the surface tension of the surface tension solution is ≥ 30 Newtons per meter (N / m). For example, the surface tension is 30 N / m, the surface tension is 40 N / m, the surface tension is 45 N / m, the surface tension is 50 N / m, the surface tension is 55 N / m, the surface tension is 60 N / m, the surface tension is 75 N / m. Thus, since the impregnation solution 20 has a certain surface tension, the capillary effect can be used to reduce the adhesion of the impregnation solution 20 on the surface of the substrate 10, but enhance the retention ability of the impregnation solution 20 in the through hole 101, thereby improving the coverage rate of the impregnation solution 20 for the through hole 101.

[0047] The surface tension solution also contains a surfactant. Thus, the surface tension of the impregnation solution 20 can be increased to enhance the retention ability of the impregnation solution 20 in the through hole 101 by using the capillary effect, and improve the coverage rate of the impregnation solution 20 for the through hole 101.

[0048] The surfactant can include alkylphenol polyoxyethylene ether, polyethylene glycol or fatty acid polyoxyethylene ester. Of course, the surfactant can also include surfactants with other names, and this application does not make specific restrictions on this. Preferably, the surfactant can include polyethylene glycol.

[0049] When the surfactant includes polyethylene glycol, the mass percentage of polyethylene glycol is 0.01 wt% - 0.1 wt%. For example, the mass percentage can be 0.02 wt%, the mass percentage can be 0.03 wt%, the mass percentage can be 0.04 wt%, the mass percentage can be 0.05 wt%, the mass percentage can be 0.06 wt%, the mass percentage can be 0.07 wt%, the mass percentage can be 0.08 wt%, the mass percentage can be 0.09 wt%, the mass percentage can be 0.1 wt%.

[0050] In one embodiment, the first concentration is 0.3 moles per liter (mol / L) - 1.2 mol / L. For example, the first concentration can be 0.3 mol / L, the first concentration can be 0.4 mol / L, the first concentration can be 0.5 mol / L, the first concentration can be 0.6 mol / L, the first concentration can be 0.7 mol / L, the first concentration can be 0.8 mol / L, the first concentration can be 0.9 mol / L, the first concentration can be 0.10 mol / L, the first concentration can be 0.11 mol / L, the first concentration can be 0.12 mol / L.

[0051] The pH value of the impregnation solution 20 can be adjusted with sulfuric acid. The pH value of the impregnation solution 20 can be 1.5 - 2.5. For example, the pH value can be 1.5, the pH value can be 1.6, the pH value can be 1.7, the pH value can be 1.8, the pH value can be 1.9, the pH value can be 2.0, the pH value can be 2.1, the pH value can be 2.2, the pH value can be 2.3, the pH value can be 2.4, the pH value can be 2.5.

[0052] As a possible implementation, under a preset vacuum degree, the substrate 10 is placed in the impregnation solution 20 and maintained for a preset duration.

[0053] Furthermore, after the substrate 10 is placed in the impregnation solution 20, the bubbles in the impregnation solution 20 can be extracted to improve the coverage rate of the impregnation solution 20 on the substrate 10.

[0054] It should be noted that the preset vacuum degree can be -0.1 MPa, -0.2 MPa, -0.3 MPa, and the present application does not make specific limitations on this.

[0055] The preset duration can be 10 minutes - 30 minutes. For example, the preset duration can be 10 minutes, the preset duration can be 15 minutes, the preset duration can be 20 minutes, the preset duration can be 25 minutes, the preset duration can be 30 minutes.

[0056] Step S103: Take out the substrate 10 from the impregnation solution 20 and dry the substrate 10 so that a solid aggregation layer 30 is formed on the inner wall of the through hole 101, and the solid aggregation layer 30 contains M salt.

[0057] The thickness range of the solid aggregation layer 30 is 50 nanometers (nm) to 200 nm. For example, the thickness is 50 nm, the thickness is 60 nm, the thickness is 70 nm, the thickness is 80 nm, the thickness is 90 nm, the thickness is 100 nm, the thickness is 150 nm, the thickness is 200 nm.

[0058] In the case where the M ion is a copper ion, the M salt can be copper sulfate. Further, the M salt can also contain copper oxide. That is, the solid collection layer 30 is a compound containing copper sulfate and / or copper oxide.

[0059] Figure 2 The following is a process schematic diagram for filling the via 101 of the substrate 10 according to another embodiment provided by the present application. As Figure 2 shown, after the substrate 10 provided with the via 101 is impregnated, the via 101 is filled with the impregnation solution 20 containing Cu2+ ions. After drying, a solid collection layer 30 containing a Cu salt is formed in the via 101.

[0060] As a possible implementation manner, at a preset temperature, the impregnation solution 20 in the via 101 of the substrate 10 is dried.

[0061] The temperature range of the preset temperature is 80°C - 100°C. For example, the preset temperature is 80°C, the preset temperature is 85°C, the preset temperature is 90°C, the preset temperature is 95°C, and the preset temperature is 100°C.

[0062] As another possible implementation manner, the impregnation solution 20 on the surface of the substrate 10 is removed, and at a preset temperature, the impregnation solution 20 in the via 101 of the substrate 10 is dried.

[0063] Exemplarily, the impregnation solution 20 on the surface of the substrate 10 can be scraped off with a squeegee. In this way, the impregnation solution 20 on the surface of the substrate 10 can be reduced, and the risk of the M salt on the surface of the substrate 10 blocking the via 101 after drying can be reduced.

[0064] It should be noted that the specific drying scheme can refer to the existing scheme. For example, drying with a hot air gun is not described in detail herein.

[0065] Step S104: Place the substrate 10 in the electroplating solution 40 for electroplating. The electroplating solution 40 fills the via 101. The electroplating solution 40 contains M ions, and the concentration of M ions in the electroplating solution is the second concentration, and the first concentration is greater than the second concentration.

[0066] The electroplating solution 40 is an unsaturated solution of M ions.

[0067] The ratio of the first concentration to the second concentration is greater than or equal to 8:1. For example, the ratio is 8:1, the ratio is 9:1, the ratio is 11:1, and the ratio is 12:1.

[0068] Figure 3 The following is a schematic diagram of an electroplating scenario according to an embodiment provided by the present application. As Figure 3 shown, the substrate 10 is placed in the electroplating solution 40, and the power supply 50 supplies power to the electroplating solution 40 through the positive electrode 60 and the negative electrode 70 for electroplating.

[0069] Since the concentration of M ions in the solid aggregation layer 30 in the through-hole 101 is higher than the concentration of M ions in the electroplating solution 40, the electrochemical reaction can preferentially occur in the through-hole 101.

[0070] Taking M as Cu as an example, during electroplating, the following electrochemical reaction occurs on the pore wall of the through-hole 101:

[0071]

[0072] Based on steps S101 - S104, compared with the existing solution of first generating a seed layer in the through-hole 101 and filling the through-hole 101, the solution of the present application provides a substrate 10 provided with a through-hole 101. Then, the substrate 10 is immersed in the impregnation solution 20 to fill the through-hole 101. Then, the substrate 10 is taken out of the impregnation solution 20 and dried. Then, the substrate 10 is placed in the electroplating solution 40 that fills the through-hole 101 for electroplating. Since the impregnation solution 20 contains Cu ions which are metal ions, the ionic concentration of Cu ions is the first concentration. After drying the substrate 10, a solid aggregation layer 30 containing Cu salt is formed on the inner wall of the through-hole 101 on the substrate 10. The electroplating solution 40 contains Cu ions, and the concentration of Cu ions in the electroplating solution is the second concentration. Since the first concentration is greater than the second concentration, the concentration of Cu ions in the solid aggregation layer 30 is higher than that of Cu ions in the electroplating solution. When electroplating with the electroplating solution, it will preferentially choose to reduce the solid aggregation layer in the through-hole 101. At this time, the Cu salt in the through-hole 101 can serve as an autocatalytic center to initiate the electroplating reaction, so that the Cu ions in the electroplating solution 40 are deposited into the through-hole 101. The surface of the substrate 10 outside the through-hole 101 inhibits the deposition of Cu ions due to the low concentration of Cu salt, and thus more Cu metal converges in the through-hole 101. Therefore, in this embodiment, it is not necessary to form a seed layer in the through-hole 101 to achieve the filling of the through-hole 101. In addition, the hole filling method provided in this embodiment does not form an excessive metal layer on the surface of the substrate 10, reducing the waste of resources.

[0073] In one design, before step S104, the substrate 10 can be immersed in the impregnation solution 20 again and dried again, that is, steps S102 - S103 are repeatedly executed.

[0074] By immersing the substrate 10 in the impregnation solution 20 and drying it multiple times, the uniformity of the distribution of Cu salt on the pore wall of the through-hole 101 can be improved.

[0075] It should be noted that the number of times the substrate 10 is immersed in the impregnation solution 20 and dried can be 1, 2, 3, 4, or 5 times. Of course, it can also be other times, and the present application does not make specific limitations on this.

[0076] Figure 4 Another process schematic diagram of the filling of the through holes 101 of the substrate 10 provided by this application is as follows. Figure 4 As shown, with the increase in the number of impregnation and drying times, on the one hand, each impregnation and drying can deposit a layer of M ions on the substrate 10, and after multiple cycles, the total load of M ions can be significantly increased; on the other hand, due to the uneven coverage caused by the surface tension of the solution or the wettability of the substrate 10 during a single impregnation, subsequent impregnations can fill the micropores or cracks formed during the previous drying, making the solid accumulation layer 30 more uniform; on the other hand, the microstructure formed after each drying (can serve as the nucleation point for the next impregnation, regulating the porosity or grain size of the final solid accumulation layer 30; on the other hand, gradient bonding: during multiple drying processes, thermal diffusion or chemical reactions may occur between M ions and the substrate 10, enhancing the bonding force between the solid accumulation layer 30 and the substrate 10, and multiple thin-layer depositions can reduce stress accumulation.

[0077] This application also provides a substrate 10, which is made by using the filling method of any through hole 101 of the substrate 10 in the filling methods of multiple through holes 101 of the substrate 10 provided by the above specific embodiments.

[0078] This application also provides an electronic device, including a substrate 10, which is made by using the manufacturing method of any substrate 10 in the manufacturing methods of multiple substrates 10 provided by the above specific embodiments. The substrate 10 provided by this application is applied to common electronic devices on the market. For example, the electronic device can be some consumer electronic products (such as computers), communication electronic products, medical devices, automotive electronics, intelligent electronic products and other terminal devices, or the electronic device can also be semi-finished devices, etc., which are not specifically limited here.

[0079] The above embodiments are used to illustrate the implementation schemes disclosed in this application and should not be construed as limitations on this application. In addition, various modifications listed herein and the changes in the methods and compositions in the application are obvious to those skilled in the art without departing from the scope and spirit of this application. Although this application has been specifically described in combination with various specific preferred embodiments of this application, it should be understood that this application should not be limited to these specific embodiments. In fact, all obvious modifications to those skilled in the art as described above to obtain the application should be included in the scope of this application.

Claims

1. A method for filling a through-hole of a substrate, characterized in that The filling method includes: Providing a substrate; through holes penetrating the substrate are provided on the substrate; Immersing the substrate in an impregnation solution, the impregnation solution contains M ions, the ionic concentration of the M ions is a first concentration, and the M ions include at least one metal ion; Taking out the substrate from the impregnation solution and drying the substrate so that a solid accumulation layer is formed on the inner wall of the through hole, and the solid accumulation layer contains M salt; Putting the substrate into an electroplating solution for electroplating; the electroplating solution fills the through hole, the electroplating solution contains the M ions, and the concentration of the M ions in the electroplating solution is a second concentration, and the first concentration is greater than the second concentration.

2. The filling method according to claim 1, wherein The impregnation solution is a surface tension solution, and the surface tension ≥ 30 N / m.

3. The filling method according to claim 1, wherein The impregnation solution is a saturated solution of M ions, and the electroplating solution is an unsaturated solution of M ions.

4. The filling method according to claim 1, characterized in that, Before placing the substrate in the electroplating solution, immersing the substrate in the impregnation solution again and drying it again.

5. The filling method according to claim 1, characterized in that The ratio of the first concentration to the second concentration is greater than or equal to 8:

1.

6. The filling method according to claim 2, wherein, The surface tension solution further contains a surfactant, and the surfactant includes polyethylene glycol.

7. The filling method according to claim 6, characterized in that, The mass percentage of the polyethylene glycol is 0.01 wt% - 0.1 wt%.

8. The filling method according to claim 1, characterized in that, The M ions are copper ions, and the impregnation solution includes CuSO4·5H2O.

9. The filling method according to claim 1, characterized in that, The first concentration is 0.3 mol / L - 1.2 mol / L.

10. The filling method according to claim 1, characterized in that, The thickness range of the solid accumulation layer is 50 nm - 200 nm.

11. The filling method according to any one of claims 1-10, characterized in that, The immersing the substrate in the impregnation solution includes: Putting the substrate into the impregnation solution under a preset vacuum degree and maintaining for a preset time.

12. A substrate, characterized in that, The substrate is made by using the filling method as described in any one of claims 1 - 11.

13. An electronic device, characterized in that, The electronic device includes the substrate as described in claim 12.

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