Filtering structure and preparation method thereof

Abstract

The invention relates to a filtering structure and a preparation method thereof, and relates to the technical field of semiconductors, the filtering structure forms a columnar filtering capacitor in a substrate, and a large capacitance value is provided under the condition that the occupied area is small. Then, a first conductive layer is formed on the first side of the substrate in the direction perpendicular to the substrate, the first conductive layer comprises a first conductive part and a second conductive part, the first conductive part is in direct contact with a first electrode layer of the filter capacitor, and the second conductive part is in direct contact with a second electrode layer of the filter capacitor. Therefore, the electrode layer of the filter capacitor can be directly used as a conductive channel or a grounding channel, a conductive path and a grounding path are shortened, and the filtering effect of the filtering structure is improved.

Description

TECHNICAL FIELD

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

[0002] In a radio frequency chip, a large-current power supply path of a power device usually needs one or a group of filter capacitors, which usually have large capacitance values to provide stable power supply for the radio frequency chip.

[0003] To achieve a large capacitance value, the existing filter capacitors have a large footprint and cannot be integrated in the radio frequency chip, so they are usually externally arranged outside the radio frequency chip. Therefore, the ground path and the conductive path of the existing filter capacitors in the filter structure are usually long, which produces large parasitic inductance, which is not conducive to high-frequency application and filtering effect. SUMMARY

[0004] Therefore, it is necessary to provide a filter structure and a preparation method thereof for reducing the ground path and the conductive path of the filter capacitor in the filter structure.

[0005] To achieve the above purpose, in one aspect, the present application provides a filter structure, comprising:

[0006] a substrate, the substrate comprising at least one first through hole penetrating through the substrate in a direction perpendicular to the substrate;

[0007] a filter capacitor located in the first through hole, the filter capacitor comprising a first electrode layer and N composite layers, where N≥1 and N is a positive integer, the first electrode layer covering an inner wall of the first through hole, the composite layer comprising a first dielectric layer and a second electrode layer, the first dielectric layer covering the first electrode layer located in the first through hole, and the second electrode layer covering the first dielectric layer in the first through hole;

[0008] a first conductive layer located on a first side of the substrate in a direction perpendicular to the substrate, the first conductive layer comprising a first conductive part and a second conductive part, the first conductive part being in contact with the first electrode layer, and the second conductive part being in contact with the second electrode layer.

[0009] In one embodiment, the filter structure further comprises:

[0010] a second conductive layer located on a second side of the substrate in a direction perpendicular to the substrate, the second side being arranged opposite to the first side, and the second conductive layer comprising a third conductive part, the third conductive part being in contact with the second electrode layer.

[0011] In one embodiment, the filter structure further comprises:

[0012] a second dielectric layer on a second side of the substrate, the second dielectric layer covering the substrate, the second conductive layer and part of the filter capacitor;

[0013] a connection structure in the second dielectric layer, extending in a direction perpendicular to the substrate, one side of the connection structure being in contact with the second conductive layer.

[0014] In one embodiment, the filter structure further comprises:

[0015] an inductor on a side of the second dielectric layer away from the substrate, the inductor being in contact with another side of the connection structure.

[0016] In one embodiment, the filter structure further comprises:

[0017] a third dielectric layer on the first side of the substrate, the first conductive layer being in the third dielectric layer.

[0018] In one embodiment, the material of the first electrode layer comprises one of copper, aluminum, aluminum-copper alloy and titanium-copper alloy.

[0019] The first dielectric layer is a high-K dielectric layer, and the material of the high-K dielectric layer comprises one of silicon nitride, silicon oxide, aluminum oxide and hafnium oxide.

[0020] In another aspect, a method for manufacturing a filter structure is also provided, comprising:

[0021] providing a substrate, the substrate comprising at least one first via hole extending through the substrate in a direction perpendicular to the substrate;

[0022] forming a filter capacitor in the first via hole, the filter capacitor comprising a first electrode layer and N composite layers, where N≥1 and N is a positive integer, the first electrode layer covering an inner wall of the first via hole, the composite layer comprising a first dielectric layer and a second electrode layer, the first dielectric layer covering the first electrode layer in the first via hole, and the second electrode layer covering the first dielectric layer in the first via hole;

[0023] forming a first conductive layer on a first side of the substrate in a direction perpendicular to the substrate, the first conductive layer comprising a first conductive part and a second conductive part, the first conductive part being in contact with the first electrode layer, and the second conductive part being in contact with the second electrode layer.

[0024] In one embodiment, after the step of forming the filter capacitor in the first via hole, the method further comprises:

[0025] forming a second conductive layer and a second dielectric layer on a second side of the substrate, the second side being opposite to the first side, the second conductive layer comprising a third conductive part, the third conductive part being in contact with the second electrode layer, the second dielectric layer covering the third conductive part;

[0026] forming a second via hole in the second dielectric layer, the second via hole extending in a direction perpendicular to the substrate and exposing the second conductive layer;

[0027] forming a connecting structure in the second via hole.

[0028] In one of the embodiments, after forming the second conductive layer and the second dielectric layer on the second side of the substrate, the method further comprises:

[0029] forming an inductor on a side of the second dielectric layer, the inductor being in contact with the connecting structure.

[0030] In one of the embodiments, forming the filter capacitor in the first via hole comprises:

[0031] sputtering a seed layer on an inner wall of the first via hole;

[0032] depositing a first electrode layer covering the inner wall of the seed layer in the first via hole;

[0033] depositing N layers of composite layers covering the first electrode layer in the first via hole, N≥1, and N is a positive integer.

[0034] Compared with the prior art, the above technical solution has the following advantages:

[0035] In the filter structure and the preparation method thereof, a substrate is provided, the substrate has at least one first via hole in a direction perpendicular to the substrate, then a filter capacitor is formed in the first via hole, the filter capacitor comprises a first electrode layer and N layers of composite layers, N≥1, and N is a positive integer, the composite layers comprise a first dielectric layer and a second electrode layer, at this time, the first electrode layer, the first dielectric layer and the second electrode layer form a columnar sandwich structure filter capacitor, which realizes providing a large capacitance value in a small area, and since the composite layers can be N layers, the controllability of the capacitance value is higher. Then a first conductive layer is formed on a first side of the substrate in a direction perpendicular to the substrate, the first conductive layer comprises a first conductive part and a second conductive part, the first conductive part is directly in contact with the first electrode layer, and the second conductive part is directly in contact with the second electrode layer, since the filter capacitor penetrates the substrate at this time, the electrode layer of the filter capacitor can be directly used as a conductive channel or a grounding channel, which shortens the conductive path and the grounding path and improves the filtering effect of the filter structure. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0037] Figure 1 A top view structural schematic diagram of a filter structure is provided for the embodiments of the present application;

[0038] Figure 2 A cross-sectional structural schematic diagram of a filter structure is provided for the embodiments of the present application;

[0039] Figure 3 A top view structural schematic diagram of a filter capacitor of a two-layer composite layer is provided for the embodiments of the present application;

[0040] Figure 4 A cross-sectional structural schematic diagram of a filter structure provided with a second conductive layer is provided for the embodiments of the present application;

[0041] Figure 5 A preparation flowchart of a filter structure is provided for the embodiments of the present application.

[0042] Legend of reference numerals: 01-substrate; 02-filter capacitor; 03-first electrode layer; 04-first dielectric layer; 05-second electrode layer; 06-seed layer; 07-first conductive layer; 071-first conductive part; 072-second conductive part; 08-second conductive layer; 081-third conductive part; 082-fourth conductive part; 09-second dielectric layer; 10-connection structure; 11-inductor; 12-third dielectric layer; 13-fourth dielectric layer. DETAILED DESCRIPTION

[0043] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the related drawings. The embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0045] It should be understood that when a layer is referred to as being "on", "adjacent", "connected" or "coupled" to another layer, it can be directly on, adjacent, connected or coupled to the other layer or intervening layers can be present. In contrast, when an element is referred to as being "directly on", "directly adjacent" or "directly coupled" to another element, there are no intervening layers present.

[0046] As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. As will be understood by those familiar with the art, the terms "includes" and / or "including", or "has" and / or "having", as well as

[0047] Based on the content in the background art, the metal-insulator-metal (MIM) capacitor is usually composed of two layers of metal electrodes and a layer of high-K dielectric layer, forming a vertically stacked parallel-plate capacitor. This capacitor has high precision, but is usually used to realize low capacitance, and if used to make filter capacitors for power supply, the area is too large, resulting in high cost. Metal-oxide-metal (MOM) capacitor utilizes the transverse electric field between the interdigital or cross-shaped metal tracks of the same metal layer to form a capacitor, and the dielectric is usually a low-K oxide layer. This capacitor has low capacitance density and low capacitance precision, and can be completed without additional processes and masks, but for filter capacitors with large capacitance requirements, multiple layers of stacking are required, or the area is expanded to achieve. Therefore, whether it is a metal-insulator-metal (MIM) capacitor or a metal-oxide-metal (MOM) capacitor, when used as a filter capacitor, the filter capacitor is external, resulting in a long ground path and a long conductive path. At this time, the parasitic inductance is large, which is not conducive to the high-frequency application of the filter structure and the filtering effect.

[0048] Based on this, the application provides a filter structure and a preparation method thereof. A substrate is provided, which has at least one first through hole in a direction perpendicular to the substrate, and then a filter capacitor is formed in the first through hole, the filter capacitor comprising a first electrode layer and N composite layers, wherein N is greater than or equal to 1 and is a positive integer, and the composite layer comprises a first dielectric layer and a second electrode layer. At this time, the first electrode layer, the first dielectric layer and the second electrode layer form a columnar sandwich structure filter capacitor, which realizes a large capacitance value in a small area, and since the composite layer can be N layers, the controllability of the capacitance value is higher. Then, a first conductive layer is formed on the first side of the substrate in a direction perpendicular to the substrate, the first conductive layer comprising a first conductive part and a second conductive part, the first conductive part being in direct contact with the first electrode layer, and the second conductive part being in direct contact with the second electrode layer. Since the filter capacitor penetrates the substrate at this time, the electrode layer of the filter capacitor can be directly used as a conductive channel or a grounding channel, thereby shortening the conductive path and the grounding path and improving the filtering effect of the filter structure.

[0049] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the application will be further described in detail below with reference to the drawings and specific embodiments.

[0050] Reference Figure 1 , Figure 1 A top view structural schematic diagram of a filter structure is provided for the embodiments of the application; reference Figure 2 , Figure 2 A cross-sectional structural schematic diagram of a filter structure is provided for the embodiments of the application; the filter structure comprises:

[0051] A substrate 01, which comprises at least one first through hole penetrating the substrate 01 in a direction perpendicular to the substrate 01;

[0052] A filter capacitor 02 located in the first through hole, the filter capacitor 02 comprising a first electrode layer 03 and N composite layers, wherein N is greater than or equal to 1 and is a positive integer, the first electrode layer 03 covering the inner wall of the first through hole, and the composite layer comprising a first dielectric layer 04 and a second electrode layer 05, the first dielectric layer 04 covering the first electrode layer 03 located in the first through hole, and the second electrode layer 05 covering the first dielectric layer 04 in the first through hole;

[0053] A first conductive layer 07 located on the first side of the substrate 01 in a direction perpendicular to the substrate 01, the first conductive layer 07 comprising a first conductive part 071 and a second conductive part 072, the first conductive part 071 being in contact with the first electrode layer 03, and the second conductive part 072 being in contact with the second electrode layer 05.

[0054] Specifically, the substrate 01 can be a glass substrate. It should be noted that the number of first through holes is not specifically limited and can be one, two, three, four, etc. The number of filter capacitors 02 required by the filter structure can be designed accordingly. In some embodiments, when multiple first through holes are provided, the multiple first through holes can be arranged in an array. The shape of the first through hole can be circular and is not specifically limited.

[0055] The filter capacitor 02 is arranged in the first through hole and includes a first electrode layer 03 and N layers of composite layers. It should be noted that N can be a positive integer greater than 1, such as 1, 2, 3, etc. Increasing the number of N can increase the capacitance of the filter capacitor 02. Therefore, the capacitance of the filter capacitor 02 can be adjusted by adjusting the number of composite layers.

[0056] The composite layer includes a first dielectric layer 04 and a second electrode layer 05. For example, only one composite layer is provided (as shown in Figure 2 When only one composite layer is provided, the filter capacitor 02 includes one layer of first electrode layer 03, one layer of first dielectric layer 04 covering the first electrode layer 03, and one layer of second electrode layer 05 covering the first dielectric layer 04. At this time, the second electrode layer 05 fills the remaining first through hole, forming a sandwiched capacitor structure as shown in Figure 2 It should be noted that the material of the second electrode layer 05 can be copper metal material. Since the filter capacitor 02 is a columnar structure and is located in the substrate 01, it almost does not occupy additional area of the filter structure, thereby improving the integration of the filter capacitor 02.

[0057] It should also be noted that a seed layer 06 can be provided between the first electrode layer 03 and the substrate 01 in the first through hole to facilitate deposition of the first electrode layer 03.

[0058] In the direction perpendicular to the substrate 01 and on the first side of the substrate 01, a first conductive layer 07 is provided. The first conductive layer 07 includes a first conductive part 071 and a second conductive part 072. It should be noted that the first conductive part 071 can be in direct contact with the first electrode layer 03, and the second conductive part 072 can be in direct contact with the second electrode layer 05. At this time, the first conductive part 071 can be directly grounded, so that the grounding path of the filter capacitor 02 in the filter structure is minimized. The second conductive part 072 can be directly connected to the power supply VCC, so that the power supply path of the filter capacitor 02 in the filter structure is minimized. At this time, the grounding path and the power supply path of the filter structure are very short, which can achieve better filtering effect. At this time, the power supply of the filter structure can be transmitted directly along the second electrode layer 05, that is, the second electrode layer 05 of the filter capacitor 02 serves as the conductive path of the filter structure, so that the conductive path is very short, further improving the filtering effect.

[0059] It should be noted that, with reference to Figure 3 , Figure 3 a top view structural schematic diagram of a filter capacitor with a two-layer composite layer provided in an embodiment of the present application; when the composite layer is a multi-layer, the second conductive part 072 can be connected to the second electrode layer 05 of the Nth layer only, at this time, a sandwich structure of multi-layer dielectric is realized, and the capacitance value of the filter capacitor can be doubled to realize a filter capacitor 02 with a large capacitance value.

[0060] In the embodiment, the first conductive part 071 is in direct contact with the first electrode layer 03, and the second conductive part 072 is in direct contact with the second electrode layer 05, since the filter capacitor 02 is through the substrate 01 at this time, the electrode layer of the filter capacitor 02 can be directly used as a conductive channel or a ground channel, thereby shortening the conductive path and the ground path and improving the filtering effect of the filter structure.

[0061] In another embodiment of the present application, with reference to Figure 4 , Figure 4 a cross-sectional structural schematic diagram of a filter structure provided with a second conductive layer in an embodiment of the present application; the filter structure further comprises:

[0062] a second conductive layer 08, located on the second side of the substrate 01 in a direction perpendicular to the substrate 01, the second side being arranged opposite to the first side, and the second conductive layer 08 comprising a third conductive part 081 in contact with the second electrode layer 05.

[0063] Specifically, the first side and the second side of the substrate 01 are two sides opposite in a direction perpendicular to the substrate 01. The first side is used for power connection and grounding, and the second side can be used for connecting other components.

[0064] The second conductive layer 08 comprises a third conductive part 081 in direct contact with the second electrode layer 05, at this time, the third conductive part 081 is used for connecting other components of the filter structure. In some embodiments, the second conductive layer 08 further comprises a fourth conductive part 082 to form other wiring.

[0065] In the embodiment, the second conductive layer 08 can improve the reliability of connecting other components.

[0066] In another embodiment of the present application, as shown in Figure 4 , the filter structure further comprises:

[0067] a second dielectric layer 09, located on the second side of the substrate 01, the second dielectric layer 09 covering the substrate 01, the second conductive layer 08 and part of the filter capacitor 02;

[0068] a connecting structure 10, located in the second dielectric layer 09 and extending in a direction perpendicular to the substrate 01, the connecting structure 10 being in contact with the second conductive layer 08.

[0069] Specifically, the second dielectric layer 09 covers the second side of the substrate 01. It should be noted that the second dielectric layer 09 is an insulating material, which can avoid failure of the filter structure.

[0070] The connecting structure 10 is further arranged in the second dielectric layer 09, and the connecting structure 10 extends in a direction perpendicular to the substrate 01 and is in contact with the second conductive layer 08, so as to connect the second conductive layer 08 and subsequent components.

[0071] In the embodiment, the second dielectric layer 09 can protect the components in the filter structure and isolate different components to avoid failure. In addition, the connecting structure 10 extends in a direction perpendicular to the substrate 01, which can further shorten the conductive path.

[0072] In another embodiment of the present application, as shown in Figure 4 The filter structure further comprises:

[0073] The inductor 11 is located on the side of the second dielectric layer 09 away from the substrate 01, and the inductor 11 is in contact with the other side of the connecting structure 10.

[0074] Specifically, the inductor 11 can be a choke inductor. In the filter structure, the choke inductor 11 has small impedance to low frequency (such as power fundamental wave), allowing useful current to pass through, achieving the filtering effect of "passing low frequency and blocking high frequency".

[0075] The inductor 11 is located on the side of the second dielectric layer 09 away from the substrate 01. After the connecting structure 10 is in contact with the inductor 11, a fourth dielectric layer 13 can be further formed on the second dielectric layer 09 and the side of the inductor 11, which can avoid damage to the inductor 11. At this time, the inductor 11 is in contact with the other side of the connecting structure 10, that is, the inductor 11 is connected to the third conductive part 081 through the connecting structure 10, thereby connecting the filter capacitor and achieving further filtering.

[0076] In another embodiment of the present application, as shown in Figure 4 The filter structure further comprises:

[0077] The third dielectric layer 12 is located on the first side of the substrate 01, and the first conductive layer 07 is located in the third dielectric layer 12.

[0078] Specifically, the third dielectric layer 12 can be an insulating material, covering the substrate 01, the first conductive layer 07 and the part of the filter capacitor 02 exposed. The first conductive layer 07 can avoid damage to the filter capacitor 02.

[0079] In the embodiment, the third dielectric layer 12 can isolate the first conductive part 071 and the second conductive part 072, prevent short circuit caused by contact of different conductive parts, ensure the circuit to be turned on according to the design logic, and improve the reliability of the filter structure.

[0080] In another embodiment of the present application, the material of the first electrode layer 03 can be one of copper, aluminum, aluminum-copper alloy, and titanium-copper alloy, and the first dielectric layer 04 is a high-K dielectric layer, which can include one of silicon nitride, silicon oxide, aluminum oxide, and hafnium oxide. Here, only an example is given, and no specific limitation is made.

[0081] Based on the above filter structure, the present application further provides a preparation method of the filter structure, referring to Figure 5 , Figure 5 a preparation flow diagram of the filter structure provided by the embodiment of the present application; the steps of the preparation method of the filter structure include:

[0082] S10: providing a substrate 01, the substrate 01 includes at least one first through hole penetrating through the substrate 01 in a direction perpendicular to the substrate 01.

[0083] In this step, the substrate 01 can be a glass substrate, and the first through hole can be prepared by a glass through hole technology (Through Glass Via, abbreviated as TGV).

[0084] The number of the first through hole is not specifically limited, which can be 1, 2, 3, 4, etc., and can be designed according to the number of filter capacitors 02 required by the filter structure.

[0085] S20: forming a filter capacitor 02 in the first through hole (as shown in Figure 2 ).

[0086] The filter capacitor 02 includes a first electrode layer 03 and N layers of composite layers, wherein N≥1 and N is a positive integer, the first electrode layer 03 covers the inner wall of the first through hole, the composite layer includes a first dielectric layer 04 and a second electrode layer 05, the first dielectric layer 04 covers the first electrode layer 03 located in the first through hole, and the second electrode layer 05 covers the first dielectric layer 04 in the first through hole.

[0087] In this step, the filter capacitor can be prepared by deposition, and the filter capacitor 02 includes the first electrode layer 03 and the N layers of composite layers. It should be noted that N can be 1, 2, 3, etc. N is a positive integer greater than 1, and the increase of the number of N can increase the capacitance value of the filter capacitor 02, so the capacitance value of the filter capacitor 02 can be adjusted by adjusting the number of layers of the composite layer.

[0088] The composite layer includes the first dielectric layer 04 and the second electrode layer 05. Here, only one composite layer is provided as an example. When only one composite layer is provided, the filter capacitor 02 includes one first electrode layer 03, one first dielectric layer 04 covering the first electrode layer 03, and one second electrode layer 05 covering the first dielectric layer 04. At this time, the second electrode layer 05 fills all the remaining first through holes, forming a columnar sandwich capacitor structure as shown in FIG. 2. Figure 2

[0089] It should be noted that the columnar sandwich capacitor structure can be cylindrical. The density of the filter capacitor 02 is proportional to the circumference of the first dielectric layer 04, the thickness of the substrate 01, and the dielectric constant of the first dielectric layer 04, and inversely proportional to the thickness of the first dielectric layer 04. The capacitance value of the filter capacitor 02 is where ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the first dielectric layer 04, r is the radius of the first dielectric layer 04, T is the thickness of the substrate 01, and d is the thickness of the first dielectric layer 04. Therefore, it is very easy to increase the capacitance value by changing the material and thickness of the first dielectric layer 04, expanding the aperture, increasing the thickness of the substrate 01, and the like.

[0090] It should be noted that the first dielectric layer 04 is a high-K dielectric layer, which can include one of silicon nitride, silicon oxide, aluminum oxide, and hafnium oxide, which is only an example and is not specifically limited.

[0091] S30: Forming a first conductive layer 07 on the first side of the substrate 01 in a direction perpendicular to the substrate 01.

[0092] The first conductive layer 07 includes a first conductive part 071 and a second conductive part 072. The first conductive part 071 is in contact with the first electrode layer 03, and the second conductive part 072 is in contact with the second electrode layer 05.

[0093] In this step, the first conductive part 071 and the second conductive part 072 formed in a direction perpendicular to the substrate 01 are not in contact. The light etching method can be used, and specific limitations are not made here. For example, a third dielectric layer 12 is first formed on the first side of the substrate 01, then a through hole is formed by light etching to expose the first electrode layer 03 and the second electrode layer 05, and then a conductive material is filled in the through hole to form the first conductive layer 07.

[0094] It should be noted that when the filter capacitor 02 is multiple, the first conductive part 071 and the second conductive part 072 can be provided multiple to connect different filter capacitors 02, i.e. multiple filter capacitors 02 are connected in parallel, thereby realizing a filter capacitor 02 array. The use of this capacitor array can achieve high capacitance density.

[0095] ​In the embodiment, the first conductive part 071 directly contacts the first electrode layer 03, and the second conductive part 072 directly contacts the second electrode layer 05. Since the filter capacitor 02 penetrates the substrate 01 at this time, the electrode layer of the filter capacitor 02 can be directly used as a conductive channel or a ground channel, the conductive path and the ground path are shortened, and the filtering effect of the filter structure is improved.

[0096] In another embodiment of the present application, after the filter capacitor 02 is formed in the first via, the following steps are further included:

[0097] In the direction perpendicular to the substrate 01, a second conductive layer 08 and a second dielectric layer 09 are formed on the second side of the substrate 01, the second side is arranged opposite to the first side, the second conductive layer 08 includes a third conductive part 081, the third conductive part 081 contacts the second electrode layer 05, and the second dielectric layer 09 covers the third conductive part 081.

[0098] A second via is formed in the second dielectric layer 09, the second via extends in the direction perpendicular to the substrate 01 and exposes the second conductive layer 08.

[0099] A connection structure 10 is formed in the second via.

[0100] Specifically, in the direction perpendicular to the substrate 01, the second conductive layer 08 is formed on the second side of the substrate 01, which can be performed by lithography. In addition to the third conductive part 081, the second conductive layer 08 also has a fourth conductive part 082 to realize other functions, such as connecting other components. The third conductive part 081 contacts the second electrode layer 05 and avoids contacting the first electrode layer 03.

[0101] Before or after the second conductive layer 08 is formed, the second dielectric layer 09 can be formed, which is not specifically limited. For example, part of the second dielectric layer 09 is first formed, then etching is performed to form a via, the second conductive layer 08 is prepared in the via, and then part of the second dielectric layer 09 is formed to cover the second conductive layer 08, the substrate 01 and the exposed area of the filter capacitor 02 to avoid damage.

[0102] Then, the second via is formed in the second dielectric layer 09, which can be formed by etching and extends in the direction perpendicular to the substrate 01 to expose the second conductive layer 08. Then, the connection structure 10 is formed by filling conductive material in the second via to provide a connection basis for subsequent component connection.

[0103] In the embodiment, the second dielectric layer 09 can protect the components in the filter structure and can isolate different components to avoid failure. In addition, the connection structure 10 extends in the direction perpendicular to the substrate 01, which can further shorten the conductive path.

[0104] In another embodiment of the present application, after the second conductive layer 08 and the second dielectric layer 09 are formed on the second side of the substrate 01, the method further comprises:

[0105] The inductor 11 is formed on one side of the second dielectric layer 09, and the inductor 11 is in contact with the connection structure 10.

[0106] Specifically, the inductor 11 can be a choke inductor 11, at this time the inductor 11 can be provided first. Then one end of the inductor 11 is in contact with the connection structure 10, and then a fourth dielectric layer 13 is formed on the side of the choke inductor away from the substrate 01. At this time, the fourth dielectric layer 13 can protect the inductor 11 and improve its reliability.

[0107] It should be noted that the inductor 11 can also be formed directly on the second dielectric layer 09, and then a fourth dielectric layer 13 is formed on the side of the inductor 11 away from the substrate 01, without specific limitation. In a radio frequency chip, when the filter structure is used to power a transistor, the other end of the inductor 11 can be connected to the transistor, and the current passes through the filter capacitor 02 and the inductor 11. Due to the short conductive path, the filtering effect is good, and the transistor can be provided with stable working voltage after filtering.

[0108] In another embodiment of the present application, the filter capacitor 02 is formed in the first through hole, comprising:

[0109] S201: sputtering a seed layer 06 on the inner wall of the first through hole;

[0110] S202: depositing a first electrode layer 03 in the first through hole to cover the inner wall of the seed layer 06;

[0111] S203: depositing N layers of composite layers in the first through hole to cover the first electrode layer 03, N≥1, and N is a positive integer.

[0112] Specifically, when forming the filter capacitor 02, the seed layer 06 can be sputtered on the inner wall of the first through hole using a sputtering process. The material of the seed layer 06 is a metal material, which provides a good basis for the subsequent deposition of the first electrode layer 03.

[0113] Then the first electrode layer 03 covering the inner wall of the seed layer 06 is deposited in the first through hole, which can be deposited by plasma enhanced chemical vapor deposition (PECVD) method.

[0114] It should be noted that one layer of composite layer is taken as an example for description, when one layer of composite layer is formed, the first dielectric layer 04 can be deposited in the first through hole to cover the inner wall of the first electrode layer 03, and then the second electrode layer 05 can be deposited in the first through hole to cover the inner wall of the first dielectric layer 04. Both can be deposited by plasma enhanced chemical vapor deposition (PECVD) method.

[0115] When the composite layer is a multi-layer, the deposition can be repeated in the same way to form the required number of layers, at this time the sandwich structure of the multi-layer medium is realized, and the capacitance value can be doubled.

[0116] In the present application, the filter structure can easily realize the change of the capacitance value of the filter capacitor 02 by adjusting the aperture of the filter capacitor 02 and the thickness of the substrate 01, and the filter capacitor 02 in the structure hardly occupies additional area, improves the integration, and the filter capacitor 02 in the filter structure has extremely short power supply end and ground end paths, and the filter effect is very good.

[0117] In the description of the present application, the description of the terms "some embodiments", "another embodiment" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are contained in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0118] The technical features of the above-described embodiments can be combined arbitrarily, and in order to make the description simple, all possible combinations of the technical features of the above-described embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0119] The above-described embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A filtering structure, characterized in that: include: a substrate, the substrate comprising at least one first through hole penetrating the substrate in a direction perpendicular to the substrate; a filter capacitor located in the first through hole, the filter capacitor comprising a first electrode layer and N composite layers, where N ≥ 1 and N is a positive integer, the first electrode layer covering an inner wall of the first through hole, the composite layer comprising a first dielectric layer and a second electrode layer, the first dielectric layer covering the first electrode layer located in the first through hole, and the second electrode layer covering the first dielectric layer in the first through hole; The first conductive layer is located on the first side of the substrate in a direction perpendicular to the substrate. The first conductive layer includes a first conductive portion and a second conductive portion. The first conductive portion contacts the first electrode layer, and the second conductive portion contacts the second electrode layer.

2. The filtering structure according to claim 1, characterized in that The filtering structure further includes: The second conductive layer is located on a second side of the substrate in a direction perpendicular to the substrate, the second side being opposite to the first side, and the second conductive layer includes a third conductive portion, which is in contact with the second electrode layer.

3. The filtering structure according to claim 2, characterized in that The filtering structure further includes: a second dielectric layer, located on the second side of the substrate, the second dielectric layer covering the substrate, the second conductive layer and a portion of the filter capacitor; The connection structure is located in the second dielectric layer and extends in a direction perpendicular to the substrate, and one side of the connection structure contacts the second conductive layer.

4. The filtering structure according to claim 3, characterized in that The filtering structure further includes: An inductor is located on a side of the second dielectric layer away from the substrate, and the inductor is in contact with the other side of the connection structure.

5. The filtering structure according to claim 1, characterized in that The filtering structure further includes: The third dielectric layer is located on the first side of the substrate, and the first conductive layer is located in the third dielectric layer.

6. The filtering structure according to claim 1, characterized in that The material of the first electrode layer includes one of copper, aluminum, aluminum-copper alloy, and titanium-copper alloy; The first dielectric layer is a high-K dielectric layer, and a material of the high-K dielectric layer includes one of silicon nitride, silicon oxide, aluminum oxide, and hafnium oxide.

7. A method for preparing a filter structure, characterized in that: include: Providing a substrate, the substrate comprising at least one first through hole penetrating the substrate in a direction perpendicular to the substrate; A filter capacitor is formed in the first through hole, the filter capacitor comprising a first electrode layer and N composite layers, where N ≥ 1 and N is a positive integer, the first electrode layer covers the inner wall of the first through hole, the composite layer comprises a first dielectric layer and a second electrode layer, the first dielectric layer covers the first electrode layer located in the first through hole, and the second electrode layer covers the first dielectric layer in the first through hole; A first conductive layer is formed on a first side of the substrate in a direction perpendicular to the substrate. The first conductive layer includes a first conductive portion and a second conductive portion. The first conductive portion contacts the first electrode layer, and the second conductive portion contacts the second electrode layer.

8. The method for preparing a filter structure according to claim 7, wherein: After forming the filter capacitor in the first through hole, the method further includes: forming a second conductive layer and a second dielectric layer on a second side of the substrate in a direction perpendicular to the substrate, the second side being arranged opposite to the first side, the second conductive layer including a third conductive portion, the third conductive portion being in contact with the second electrode layer, and the second dielectric layer covering the third conductive portion; forming a second through hole in the second dielectric layer, wherein the second through hole extends in a direction perpendicular to the substrate and exposes the second conductive layer; A connection structure is formed in the second through hole.

9. The method for preparing a filter structure according to claim 8, wherein: After forming the second conductive layer and the second dielectric layer on the second side of the substrate, the method further includes: An inductor is formed on one side of the second dielectric layer, and the inductor is in contact with the connection structure.

10. The method for preparing a filter structure according to claim 7, wherein: The forming of a filter capacitor in the first through hole includes: sputtering a seed layer on an inner wall of the first through hole; depositing a first electrode layer in the first through hole to cover an inner wall of the seed layer; N composite layers covering the first electrode layer are deposited in the first through hole, where N≥1 and N is a positive integer.

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