High-performance coupling filter and preparation method

Abstract

The invention provides a high-performance coupling filter and a preparation method, and relates to the technical field of filters, and the preparation method comprises the steps: providing a substrate; an insulating layer is deposited on a substrate, then groove sets are machined in the front face and the back face of the substrate respectively, each groove set comprises a plurality of grooves, a through hole is machined in one end of the substrate, and the two ends of the through hole penetrate through the front face and the back face of the substrate respectively; respectively forming a metal filling layer in the groove, forming a metal connecting column in the through hole and forming a metal electroplating layer on the front surface and the back surface of the substrate through an electroplating process; removing the metal electroplated layer through a chemical mechanical polishing process; and forming dielectric passivation layers on the front surface and the back surface of the substrate respectively. In the invention, the coil is combined with the substrate groove technology through the substrate back surface rewiring technology, so that the wiring with high aspect ratio is realized, the narrower line distance is realized, the coupling of the coil is enhanced, the loss of the wiring is reduced, and the better performance of the filter is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of filters, and in particular to a high-performance coupling filter and a preparation method thereof. Background Art

[0002] The rapid popularity of portable electronic products, wearable smart devices and systems has triggered a strong interest in the miniaturization and integration of various product modules and components in the industry and academia. The transmission protocol in the communication system may include the use of single-ended signals, differential signals, or a combination of single-ended and differential signals. For example, single-ended signals are suitable for low-speed data transmission systems; but in high-speed data transmission systems, differential signal data transmission systems with better noise immunity are used. This type of system includes mobile electronic devices such as smart phones, tablets, computers, and systems containing universal serial bus (USB) applications. In addition to noise immunity, it is best to include protection against large transient voltage and current spikes that can damage these systems. Noise filters (including common mode filters (CMF)) and electrostatic discharge (ESD) protection circuits are installed on the printed circuit board (PCB) together with other circuits of the communication system to reduce common mode noise on differential signal lines and suppress large transient current spikes. However, this configuration of components will occupy a large area on the PCB, which is disadvantageous in mobile electronic products. In addition, ESD protection circuits are made of low-resistivity substrates to accommodate the high currents encountered during ESD events; however, eddy currents exist on low-resistivity substrates that can reduce filtering performance, so it is not advisable to manufacture filtering components such as inductors on low-resistivity substrates.

[0003] The process of making a variety of integrated miniaturized common-mode filters is to use the back-end process on the silicon wafer, through the electroplating of copper and the lamination of dielectric layer coating, to achieve the coupling between the single-layer coils. Under the same conditions, it is hoped that the coil can achieve a larger thickness, and the smaller the line width and line spacing, the better. However, due to the limitation of the electroplating process, the existing filters can usually only achieve the level of routing thickness / line width / spacing of about 1:1:1, and the routing resistance loss is relatively high. Summary of the invention

[0004] The present invention provides a high-performance coupling filter and a preparation method thereof, which are used to solve the technical problem that the existing filter can usually only achieve a wiring thickness / line width / spacing of about 1:1:1 and the wiring resistance loss is relatively high.

[0005] In order to solve the above technical problems, the present invention discloses a method for preparing a high-performance coupled filter, comprising the following steps:

[0006] Step 1: providing a substrate;

[0007] Step 2: depositing an insulating layer on the substrate, and then processing groove groups on the front and back sides of the substrate respectively, the groove groups including a plurality of grooves, and processing a through hole at one end of the substrate, the two ends of the through hole respectively passing through the front side of the substrate and the back side of the substrate;

[0008] Step 3: forming a metal filling layer in the groove, a metal connecting column in the through hole, and a metal electroplating layer on the front and back sides of the substrate respectively through an electroplating process;

[0009] Step 4: Remove the metal plating layer through a chemical mechanical polishing process;

[0010] Step 5: Form a dielectric passivation layer on the front side and the back side of the substrate respectively.

[0011] Preferably, in step 1, the substrate material is at least one of silicon, silicon carbide, germanium, gallium arsenide or other III / V group compound semiconductors.

[0012] Preferably, in step 2, the insulating layer is made of insulating material.

[0013] Preferably, in step 2, the groove aspect ratio is greater than or equal to 2 and less than or equal to 30.

[0014] Preferably, in step 2, the plurality of grooves are arranged at equal intervals along the length direction of the substrate.

[0015] Preferably, in step 2, the groove group on the front side of the substrate is symmetrically arranged with the groove group on the back side of the substrate.

[0016] Preferably, in step 3, the formation of the metal connecting column comprises the following steps:

[0017] Step 301: firstly sputtering a metal seed layer on the periphery of the through hole on the front side of the substrate, and then electroplating the front side of the substrate by an electroplating process to form a metal filling layer in the groove on the front side of the substrate, and at the same time, forming a sealing layer between the metal seed layers, the sealing layer is used to seal the through hole on the front side of the substrate;

[0018] Step 302: Turning over the substrate so that the back side of the substrate faces upward;

[0019] Step 303: a metal filling layer is formed in the groove on the back side of the substrate through an electroplating process. At the same time, the electroplated metal is filled into the through hole from the through hole on the back side of the substrate. The electroplated metal fills the through hole to form a metal connecting column.

[0020] Preferably, in step 5, a first connection hole is opened on the dielectric passivation layer, and one end of the first connection hole extends to the surface of the metal filling layer.

[0021] Preferably, in step 5, a metal routing layer is first set on the front and back sides of the substrate, the metal routing layer is respectively connected to the metal filling layer and the metal connecting column, and then a second connecting hole is opened on the dielectric passivation layer, and one end of the second connecting hole extends to the surface of the metal routing layer.

[0022] The present application also provides a high-performance coupling filter, which is prepared by the above-mentioned preparation method, including a substrate, a plurality of grooves symmetrically arranged inside the front and back sides of the substrate, a metal filling layer arranged in the grooves, a through hole arranged at one end of the substrate, a metal connecting column arranged in the through hole, and a dielectric passivation layer arranged on the front and back sides of the substrate.

[0023] The technical solution of the present invention has the following advantages: the present invention provides a high-performance coupling filter and a preparation method, which relates to the technical field of filters. The preparation method includes providing a substrate; depositing an insulating layer on the substrate, and then processing a groove group on the front and back of the substrate respectively, the groove group includes a plurality of grooves, and processing a through hole at one end of the substrate, and the two ends of the through hole respectively penetrate the front and back of the substrate; forming a metal filling layer in the groove, forming a metal connecting column in the through hole, and forming a metal electroplating layer on the front and back of the substrate respectively through an electroplating process; removing the metal electroplating layer through a chemical mechanical polishing process, and polishing the metal electroplating layer to the surface of the substrate, and the method can realize a high aspect ratio t / w, and a structure with a small line width w and a small line spacing s, wherein a general deep silicon etching process can realize a structure with an aspect ratio as high as 30:1, which fully meets the requirements of the use structure; forming a dielectric passivation layer on the front and back of the substrate. In the present invention, the coil is combined with the substrate back rewiring technology and the substrate groove technology to realize a high aspect ratio routing, and at the same time realize a narrow line spacing, enhance the coupling of the coil and reduce the loss of the routing, so that the filter can achieve better performance.

[0024] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the devices particularly pointed out in the written description and the drawings of the description.

[0025] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 A schematic diagram of the steps of a method for preparing a high performance coupled filter according to the present invention;

[0028] Figure 2It is a schematic diagram of the existing filter structure;

[0029] Figure 3 It is a schematic diagram of the substrate structure in the present invention;

[0030] Figure 4 It is a schematic diagram of the groove and through hole structure in the present invention;

[0031] Figure 5 It is a schematic diagram of the structure of the metal filling layer, the metal connecting column and the metal electroplating layer in the present invention;

[0032] Figure 6 This is a schematic diagram of the structure of the substrate after being processed by a chemical mechanical polishing process in the present invention;

[0033] Figure 7 A schematic diagram of the structure of a high performance coupling filter in the present invention;

[0034] Figure 8 Another structural schematic diagram of the high performance coupling filter in the present invention;

[0035] Fig. 9 A schematic diagram of a metal seed layer during the formation of a metal connection column of the present invention;

[0036] Fig.10 A schematic diagram of a sealing layer during the formation of a metal connecting column of the present invention;

[0037] Fig.11 A schematic diagram of flipping a substrate during the formation of a metal connection column of the present invention;

[0038] Fig.12 It is a schematic diagram of forming the metal connecting column in the present invention.

[0039] In the figure: 1. substrate; 2. groove; 3. through hole; 4. metal filling layer; 5. metal connecting column; 6. metal electroplating layer; 7. dielectric passivation layer; 8. metal seed layer; 9. sealing layer; 10. first connecting hole; 11. metal routing layer; 12. second connecting hole. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0041] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions and technical features between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0042] Example 1

[0043] The embodiment of the present invention provides a method for preparing a high performance coupled filter. Figure 1-Figure 12 As shown, the following steps are included:

[0044] Step 1: providing a substrate 1;

[0045] Step 2: depositing an insulating layer on the substrate 1, and then processing two groups of grooves on the front and back sides of the substrate 1, respectively. The two groups of grooves include a plurality of grooves 2, and processing a through hole 3 at one end of the substrate 1, and the two ends of the through hole 3 respectively penetrate the front side and the back side of the substrate 1;

[0046] Step 3: forming a metal filling layer 4 in the groove 2, a metal connecting column 5 in the through hole 3, and a metal electroplating layer 6 on the front and back sides of the substrate 1 respectively through an electroplating process;

[0047] Step 4: removing the metal plating layer 6 by chemical mechanical polishing process;

[0048] Step 5: Form a dielectric passivation layer 7 on the front side of the substrate 1 and the back side of the substrate 1 respectively.

[0049] The working principle and beneficial effects of the above technical solution are as follows: A process for an integrated common mode filter is to use a back-end process on a silicon wafer to achieve this by electroplating copper and laminating a dielectric layer, such as Figure 2As shown, the common winding copper coil is about 5um thick, and the line width and line spacing is also 5um, or even greater than 5um. It can be seen that the existing filter can usually only achieve a wiring thickness / line width / spacing of about 1:1:1, and the wiring resistance loss is relatively high. In order to reduce the wiring resistance loss and enhance the coupling of the coil, the present application provides a high-performance coupling filter preparation method, including the following steps: first providing a substrate 1, then depositing an insulating layer on the substrate 1, and then processing 2 groups of grooves on the front and back sides of the substrate 1, respectively, the groove 2 group includes a plurality of grooves 2, preferably, the groove 2 has a depth of 10μm, and the spacing between the grooves 2 is 2μm, thereby improving the aspect ratio of the groove 2 and reducing the spacing between the grooves 2, and processing a through hole 3 at one end of the substrate 1, and the through hole 3 is divided into two ends. The metal filling layer 4 is formed in the groove 2, the metal connecting column 5 is formed in the through hole 3, and the metal electroplating layer 6 is formed on the front and back of the substrate 1 respectively by electroplating process, wherein the metal filling layer 4 fills the inside of the groove 2 to form a wiring layer, so as to realize the wiring with high aspect ratio, and the electroplating metal can be selected from metal copper, and the through hole 3 is set, and the metal connecting column 5 is formed in the through hole 3, and the through hole 3 technology is used to facilitate the subsequent connection; then the metal electroplating layer 6 is removed by chemical mechanical polishing process; finally, the dielectric passivation layer 7 is formed on the front and back of the substrate 1 respectively, and the dielectric passivation layer 7 is used to protect the device from moisture and humidity, etc., and the conventional material of the dielectric passivation layer 7 can be organic polymer materials or inorganic nitride oxide materials. In the present invention, based on the MEMS process, the coil is combined with the substrate 1 back rewiring technology and the substrate 1 groove 2 technology to realize the wiring with high aspect ratio, and at the same time, a narrow line spacing is realized, the coupling of the coil is enhanced, and the loss of the wiring is reduced, so that the filter can achieve better performance.

[0050] Example 2

[0051] On the basis of the above-mentioned embodiment 1, in step 1, the substrate 1 material adopts at least one material selected from silicon, silicon carbide, germanium, gallium arsenide or other III / V group compound semiconductors.

[0052] The working principle and beneficial effects of the above technical solution are as follows: the substrate 1 can have high resistance characteristics or low resistance characteristics. In order to improve the radio frequency performance, a high resistance silicon substrate 1 is often used.

[0053] Example 3

[0054] Based on embodiment 1 or 2, in step 2, the insulating layer is made of insulating material;

[0055] The aspect ratio of groove 2 is greater than or equal to 2 and less than or equal to 30;

[0056] A plurality of grooves 2 are arranged at equal intervals along the length direction of the substrate 1;

[0057] The two groups of grooves on the front side of the substrate 1 are symmetrically arranged with the two groups of grooves on the back side of the substrate 1 .

[0058] The working principle and beneficial effects of the above technical solution are as follows: a layer of insulating material is deposited on the substrate 1 to form an insulating layer, which is used as a mask for etching the substrate 1, or a photoresist film is used to form a groove 2 with a high aspect ratio in the substrate 1 through deep silicon etching and other processes. The groove 2 has a thickness of 10 μm and a spacing of 2 μm. The grooves 2 etched on the front and back sides of the substrate 1 are used for routing to achieve routing with a high aspect ratio. Multiple grooves 2 are arranged at equal intervals and have a spacing of 2 μm, which is smaller than the existing 5 μm spacing, further achieving a narrower line pitch, enhancing the coupling of the coil and reducing the loss of the routing, so that the filter can achieve better performance.

[0059] Example 4

[0060] On the basis of any one of Examples 1-3, Figure 9-12 As shown, in step 3, the formation of the metal connecting column 5 includes the following steps:

[0061] Step 301: firstly, a metal seed layer 8 is sputtered on the periphery of the through hole 3 on the front side of the substrate 1, and then the front side of the substrate 1 is electroplated by an electroplating process to form a metal filling layer 4 in the groove 2 on the front side of the substrate 1. At the same time, a sealing layer 9 is formed between the metal seed layers 8, and the sealing layer 9 is used to seal the through hole 3 on the front side of the substrate 1;

[0062] Step 302: Turn over the substrate 1 so that the back side of the substrate 1 faces upward;

[0063] Step 303: A metal filling layer 4 is formed in the groove 2 on the back side of the substrate 1 through an electroplating process. At the same time, the electroplated metal is filled into the through hole 3 from the back side of the substrate 1. The electroplated metal fills the through hole 3 to form a metal connecting column 5.

[0064] The working principle and beneficial effects of the above technical scheme are as follows: when preparing the metal connecting column 5, the front side of the substrate 1 is firstly made to face upward, and a metal seed layer 8 is sputtered on the outer periphery of the upper end of the through hole 3 on the front side of the substrate 1, and then the front side of the substrate 1 is electroplated by an electroplating process, and the electroplated metal forms a metal filling layer 4 in the groove 2 on the front side of the substrate 1. At the same time, the electroplated metal forms a sealing layer 9 between the metal seed layers 8, and the sealing layer 9 can seal the through hole 3 on the front side of the substrate 1; after the metal electroplating layer 6 on the front side of the substrate 1 is formed, the substrate 1 is turned over so that the back side of the substrate 1 faces upward; then the back side of the substrate 1 is processed by an electroplating process, and the electroplated metal fills the groove 2, and forms a metal filling layer 4 in the groove 2 on the back side of the substrate 1. At the same time, the electroplated metal is filled from the through hole 3 on the back side of the substrate 1 into the through hole 3, and the electroplated metal fills the through hole 3 to form a metal connecting column 5. Through the above scheme, the voids generated inside the through hole 3 during the electroplating process can be reduced, thereby reducing the pore defects generated during the formation process of the metal connecting column 5, improving the preparation quality of the metal connecting column 5, and enhancing the performance of the metal connecting column 5.

[0065] Example 5

[0066] On the basis of any one of Examples 1-4, Figure 7 As shown, in step 5, a first connection hole 10 is opened on the dielectric passivation layer 7, and one end of the first connection hole 10 extends to the surface of the metal filling layer 4.

[0067] The working principle and beneficial effects of the above technical solution are as follows: after forming the dielectric passivation layer 7, a first connection hole 10 is opened at the position where the signal needs to be connected in the dielectric passivation layer 7, thereby exposing the signal pad, which is convenient for external connection with the metal filling layer 4 or the metal connecting column 5. The double-sided coil signal can be connected via external signal connection, or through the metal connecting column 5 in the through hole 3 of the substrate 1, and the signal line of the upper and lower coupled coils is formed with the help of the packaged connection.

[0068] Example 6

[0069] On the basis of any one of Examples 1-4, Figure 8 As shown, in step 5, a metal routing layer 11 is first set on the front side and the back side of the substrate 1, and the metal routing layer 11 is respectively connected to the metal filling layer 4 and the metal connecting column 5, and then a second connecting hole 12 is opened on the dielectric passivation layer 7, and one end of the second connecting hole 12 extends to the surface of the metal routing layer 11.

[0070] The working principle and beneficial effects of the above technical solution are as follows: before forming the dielectric passivation layer 7, a metal routing layer 11 is first made on the front and back sides of the substrate 1, and the metal routing layer 11 is connected to the metal filling layer 4 and the metal connecting column 5 respectively. The metal routing layer 11 is made of metal copper material, and then the dielectric passivation layer 7 is formed, and a second connecting hole 12 is opened on the dielectric passivation layer 7, which is connected to the metal routing layer 11 through an external connection to achieve interconnection with other devices.

[0071] The present application also provides a high-performance coupling filter, which is prepared by the above-mentioned preparation method, such as Figure 7 or Figure 8 As shown, it includes a substrate 1, a plurality of grooves 2 are symmetrically arranged inside the front and back sides of the substrate 1, a metal filling layer 4 is arranged in the groove 2, a through hole 3 is arranged at one end of the substrate 1, a metal connecting column 5 is arranged in the through hole 3, and a dielectric passivation layer 7 is arranged on the front and back sides of the substrate 1.

[0072] The filter achieves a high aspect ratio routing and a narrow line spacing, thereby enhancing the coupling of the coil and reducing the routing loss, thereby improving the performance of the filter.

[0073] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0074] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0075] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for preparing a high-performance coupled filter, characterized in that: The following steps are involved: Step 1: providing a substrate (1); Step 2: depositing an insulating layer on the substrate (1), and then processing a groove (2) group on the front and back sides of the substrate (1), wherein the groove (2) group includes a plurality of grooves (2), and processing a through hole (3) at one end of the substrate (1), wherein both ends of the through hole (3) respectively penetrate the front side of the substrate (1) and the back side of the substrate (1); Step 3: forming a metal filling layer (4) in the groove (2), forming a metal connecting column (5) in the through hole (3), and forming a metal electroplating layer (6) on the front and back sides of the substrate (1) respectively through an electroplating process; Step 4: removing the metal plating layer (6) by chemical mechanical polishing process; Step 5: forming a dielectric passivation layer (7) on the front side of the substrate (1) and the back side of the substrate (1) respectively.

2. A method for preparing a high performance coupled filter according to claim 1, characterized in that: In step 1, the substrate (1) is made of at least one material selected from silicon, silicon carbide, germanium, gallium arsenide or other III / V group compound semiconductors.

3. The method for preparing a high performance coupled filter according to claim 1, characterized in that: In step 2, the insulating layer is made of insulating material.

4. The method for preparing a high performance coupled filter according to claim 1, characterized in that: In step 2, the aspect ratio of the groove (2) is greater than or equal to 2 and less than or equal to 30.

5. The method for preparing a high performance coupled filter according to claim 1, characterized in that: In step 2, a plurality of grooves (2) are arranged at equal intervals along the length direction of the substrate (1).

6. The method for preparing a high performance coupled filter according to claim 1, characterized in that: In step 2, the groove (2) group on the front side of the substrate (1) is symmetrically arranged with the groove (2) group on the back side of the substrate (1).

7. The method for preparing a high performance coupled filter according to claim 1, characterized in that: In step 3, the formation of the metal connecting column (5) includes the following steps: Step 301: first, a metal seed layer (8) is sputtered on the periphery of the through hole (3) on the front side of the substrate (1), and then the front side of the substrate (1) is electroplated by an electroplating process to form a metal filling layer (4) in the groove (2) on the front side of the substrate (1). At the same time, a sealing layer (9) is formed between the metal seed layers (8), and the sealing layer (9) is used to seal the through hole (3) on the front side of the substrate (1); Step 302: Turning over the substrate (1) so that the back side of the substrate (1) faces upward; Step 303: A metal filling layer (4) is formed in the groove (2) on the back side of the substrate (1) through an electroplating process. At the same time, the electroplated metal is filled into the through hole (3) from the through hole (3) on the back side of the substrate (1). The electroplated metal fills the through hole (3) to form a metal connecting column (5).

8. The method for preparing a high performance coupled filter according to claim 1, characterized in that: In step 5, a first connection hole (10) is opened on the dielectric passivation layer (7), and one end of the first connection hole (10) extends to the surface of the metal filling layer (4).

9. The method for preparing a high performance coupled filter according to claim 1, characterized in that: In step 5, a metal wiring layer (11) is firstly provided on the front side of the substrate (1) and the back side of the substrate (1), and the metal wiring layer (11) is respectively connected to the metal filling layer (4) and the metal connecting column (5), and then a second connecting hole (12) is opened on the dielectric passivation layer (7), and one end of the second connecting hole (12) extends to the surface of the metal wiring layer (11).

10. A high-performance coupling filter, prepared by a high-performance coupling filter preparation method according to any one of claims 1 to 9, characterized in that: The high-performance coupling filter comprises a substrate (1), a plurality of grooves (2) are symmetrically arranged inside the front and back sides of the substrate (1), a metal filling layer (4) is arranged inside the grooves (2), a through hole (3) is arranged at one end of the substrate (1), a metal connecting column (5) is arranged inside the through hole (3), and a dielectric passivation layer (7) is arranged on the front and back sides of the substrate (1).

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