Transmission line structure and preparation method thereof

Abstract

The invention discloses a transmission line structure and a preparation method thereof. The transmission line structure comprises a first substrate, a first shielding layer, a second substrate and an inner conductor, a first through hole is formed in the first substrate, and the first through hole penetrates through the first substrate in the direction perpendicular to the surface of the first substrate; the first shielding layer is arranged on one side of the first substrate and covers an opening, in the first surface of the first substrate, of the first through hole; the second substrate is arranged on the side, away from the first shielding layer, of the first substrate, and the second substrate, the first through hole and the first shielding layer form a cavity; the inner conductor is located in the cavity, the inner conductor and the first shielding layer are arranged in a spaced mode, and the first through hole which is mutually insulated penetrates through the first substrate, so that the depth of the first through hole is the same as the thickness of the first substrate, and the first substrate is easily and accurately machined to be small in thickness, so that the depth of the first through hole can be accurately controlled to be small in size; and the processing precision of the transmission line structure is ensured, so that higher processing precision of an integrated circuit is realized.

Description

Technical Field

[0001] This invention relates to the field of microstructure technology, and in particular to a transmission line structure and its fabrication method. Background Art

[0002] Integrated circuits are miniature electronic devices or components that can be widely used in fields such as communications, automotive electronics, medical instruments and equipment, industrial automation and control systems, military, and aerospace.

[0003] Transmission line structures commonly used in integrated circuits for signal transmission are multilayer copper structures formed on wafers through surface micromachining (photolithography, electroplating, CMP, etc.). With the development of technology, the demand for thinner and higher-frequency integrated circuits is increasing. Existing transmission line structures have problems such as complex processes, large height, structural instability, and poor high-frequency signal transmission quality. Summary of the Invention

[0004] This application provides a transmission line structure and its fabrication method to solve the technical problems of large size and low precision of existing integrated circuit signal transmission line structures.

[0005] In view of the above problems, this application is made in order to provide a transmission line structure and a method for fabricating the same that overcomes or at least partially solves the above problems.

[0006] In a first aspect, a transmission line structure is provided, comprising: a first substrate, a first shielding layer, a second substrate, and an inner conductor;

[0007] The first substrate is provided with a first through hole, which penetrates the first substrate in a direction perpendicular to the surface of the first substrate;

[0008] The first shielding layer is disposed on one side of the first substrate, covering the opening of the first through-hole on the first surface of the first substrate;

[0009] The second substrate is disposed on the side of the first substrate away from the first shielding layer, and the second substrate, the first via, and the first shielding layer form a cavity;

[0010] The inner conductor is located inside the cavity, spaced apart from the first shielding layer, and is insulated from it.

[0011] Preferably, the transmission line structure further includes a second shielding layer;

[0012] The second substrate is provided with a second through hole, which penetrates the second substrate along a direction perpendicular to the surface of the second substrate, and the second through hole is connected to the first through hole;

[0013] The second shielding layer is disposed on the side of the second substrate away from the first substrate, covering the opening of the second through hole on the second surface of the second substrate, the second surface being the surface of the second substrate away from the first substrate; the cavity is formed by the second shielding layer, the second through hole, the first through hole and the first shielding layer, the inner conductor and the second shielding layer are spaced apart and insulated from each other.

[0014] Preferably, the transmission line structure further includes a third shielding layer and a fourth shielding layer. The third shielding layer covers at least the sidewall of the first through-hole and the third surface of the first substrate away from the first shielding layer, with the third surface opposite to the first surface. The fourth shielding layer covers at least the sidewall of the second through-hole and the fourth surface of the second substrate away from the second shielding layer, with the fourth surface opposite to the second surface. The cavity is formed by the second shielding layer, the fourth shielding layer of the second through-hole, the third shielding layer of the first through-hole, and the first shielding layer. The inner conductor is spaced apart from the third shielding layer and the fourth shielding layer and is insulated from each other.

[0015] Preferably, the thickness of the first shielding layer in the direction perpendicular to the surface of the first substrate is greater than the thickness of the third shielding layer in the direction perpendicular to the sidewall of the first via; and the thickness of the second shielding layer in the direction perpendicular to the surface of the second substrate is greater than the thickness of the fourth shielding layer in the direction perpendicular to the sidewall of the second via.

[0016] Preferably, in a direction perpendicular to the surface of the first substrate, the distance between the first shielding layer and the second shielding layer is equal to the distance between the first surface and the second surface.

[0017] Preferably, the transmission line structure further includes a support structure disposed within the cavity and located between the inner conductor and the first shielding layer.

[0018] Preferably, the first substrate has a groove on the side away from the second substrate, the groove is connected to the first through hole in a direction perpendicular to the first surface, the first shielding layer at least covers the groove, and the opening of the first through hole is located within the area of ​​the opening of the groove in the orthogonal projection of the first shielding layer.

[0019] Secondly, this application also provides a transmission cable that may include N or more transmission line structures as described in the first aspect, where N is a positive integer greater than or equal to 1.

[0020] Optionally, N is a positive integer greater than or equal to 3. A transmission line structure with more than N transmission lines includes one first transmission line and at least two second transmission lines, with at least one end of the first transmission line connected to at least two second transmission lines respectively. The first transmission line can serve as the backbone, and the at least two second transmission lines can serve as branches of the backbone.

[0021] Thirdly, this application also provides an electronic device, including a substrate, M electronic devices, and a transmission line structure as described in the first aspect, where M is a positive integer greater than or equal to 1.

[0022] M electronic devices and transmission line structures can be mounted on a substrate, and the electronic devices can be interconnected through the transmission line structures. Each electronic device can be connected to other external devices or other electronic devices via the transmission line structures. Alternatively, when an electronic device includes multiple electronic devices, the different electronic devices can also be connected through transmission line structures.

[0023] Fourthly, a method for fabricating a transmission line structure is provided, comprising:

[0024] Provide a first substrate and a second substrate;

[0025] A first shielding layer is formed on one side of the first substrate;

[0026] A first through-hole is formed in a direction perpendicular to the surface of the first substrate, and the first shielding layer covers the opening of the first through-hole on the first surface of the first substrate;

[0027] An inner conductor is formed that is spaced apart from and insulated from the first shielding layer;

[0028] The second substrate is bonded to the side of the first substrate away from the first shielding layer, so that the second substrate, the first via, and the first shielding layer form a cavity enclosing the inner conductor, thus obtaining a transmission line structure.

[0029] Preferably, the method further includes:

[0030] A second shielding layer is formed on one side of the second substrate;

[0031] A second through-hole is formed in a direction perpendicular to the surface of the second substrate, so that the second shielding layer covers the opening of the second through-hole on the second surface of the second substrate;

[0032] Bonding the second substrate to the side of the first substrate away from the first shielding layer, thereby forming a cavity with the second substrate, the first via, and the first shielding layer, includes:

[0033] The side of the second substrate away from the second shielding layer is bonded to the side of the first substrate away from the first shielding layer, so that the second through hole is connected to the first through hole, and the second shielding layer, the second through hole, the first through hole and the first shielding layer form a cavity surrounding the inner conductor, wherein the inner conductor and the second shielding layer are spaced apart and mutually insulated.

[0034] Preferably, the method further includes:

[0035] A third shielding layer is formed on the sidewall of the first through hole and on the third surface of the first substrate away from the first shielding layer, with the third surface being disposed opposite to the first surface;

[0036] A fourth shielding layer is formed on the sidewall of the second through hole and on the fourth surface of the second substrate away from the second shielding layer, with the fourth surface being disposed opposite to the second surface;

[0037] The side of the second substrate away from the second shielding layer is bonded to the side of the first substrate away from the first shielding layer, so that the second via is connected to the first via. The second shielding layer, the second via, the first via, and the first shielding layer form a cavity enclosing the inner conductor, including:

[0038] The side of the second substrate away from the second shielding layer is fastened to the side of the first substrate away from the first shielding layer, and the third shielding layer on the surface of the first substrate is bonded to the fourth shielding layer on the surface of the second substrate, so that the second shielding layer, the fourth shielding layer of the second through hole, the third shielding layer of the first through hole and the first shielding layer form a cavity surrounding the inner conductor, wherein the inner conductor is spaced apart from the third shielding layer and the fourth shielding layer and is mutually insulated.

[0039] The technical solution provided in this application has at least the following technical effects or advantages:

[0040] The transmission line structure and its fabrication method provided in this application have two aspects. First, the first via penetrates the first substrate, so the depth of the first via is the same as the thickness of the first substrate. Since the first substrate can be easily and precisely fabricated to a very small thickness, the depth of the first via can be precisely controlled within a very small dimension, ensuring the fabrication accuracy of the transmission line structure and thus achieving higher fabrication accuracy for integrated circuits. Second, the first via, the first shielding layer, and the second substrate can form a cavity to accommodate the inner conductor. The depth of the first via determines the size of the cavity, which in turn determines the size of the transmission line structure. By controlling the reduction of the thickness of the first substrate, the depth of the first via can be precisely controlled, thereby reducing the size of the transmission line structure and achieving thinner and lighter integrated circuits.

[0041] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0043] Figure 1 A cross-sectional schematic diagram of a transmission line structure provided in an embodiment of this application;

[0044] Figure 2 A cross-sectional schematic diagram of a transmission line structure provided in an embodiment of this application;

[0045] Figure 3 A cross-sectional schematic diagram of a transmission line structure provided in an embodiment of this application;

[0046] Figure 4 A cross-sectional schematic diagram of a transmission line structure provided in an embodiment of this application;

[0047] Figure 5 A cross-sectional schematic diagram of a transmission line structure provided in an embodiment of this application;

[0048] Figure 6 A cross-sectional schematic diagram of a transmission line structure provided in an embodiment of this application;

[0049] Figure 7 A cross-sectional schematic diagram of a transmission line structure provided in an embodiment of this application;

[0050] Figure 8 This is a flowchart of the transmission line structure fabrication method in the embodiments of this application;

[0051] Figure 9 A step diagram illustrating a method for fabricating a transmission line structure according to an embodiment of this application;

[0052] Figure 10 A step diagram illustrating a method for fabricating a transmission line structure according to an embodiment of this application;

[0053] Figure 11 A step diagram illustrating a method for fabricating a transmission line structure according to an embodiment of this application;

[0054] Figure 12 A cross-sectional schematic diagram of a transmission line structure provided in an embodiment of this application;

[0055] Figure 13 This is a structural diagram of an electronic device provided in an embodiment of this application. DETAILED DESCRIPTION

[0056] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings.

[0057] The accompanying drawings illustrate various structural schematics according to embodiments of this application. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0058] To facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with essentially the same function and effect. For example, the first value and the second value are only used to distinguish different values ​​and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" are not necessarily different.

[0059] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0060] In the context of this disclosure, when a layer / component is referred to as being "above" another layer / component, that layer / component may be directly above the other layer / component, or there may be an intermediate layer / component between them. Additionally, if a layer / component is "above" another layer / component in one orientation, then when the orientation is reversed, that layer / component may be "below" the other layer / component. In the context of this disclosure, similar or identical components may be denoted by the same or similar reference numerals.

[0061] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to specific implementation methods. It should be understood that the embodiments of this disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0062] To facilitate understanding of the transmission line structure provided in the embodiments of this application, its application scenarios will be introduced first below.

[0063] Transmission lines are used in electronic devices, which are composed of electronic components and capable of processing, storing, transmitting, and displaying electronic signals or data. Transmission lines connect various electronic components within electronic devices, enabling signal transmission and interaction within the circuit board and ensuring the normal operation of the electronic equipment.

[0064] Electronic components can be active devices, such as discrete devices like transistors and field-effect transistors; they can also be analog integrated circuit devices such as operational amplifiers and analog multipliers; and they can be digital integrated circuit devices such as basic logic gates, microprocessors, and programmable logic devices. Electronic components can also be passive devices, such as chips, resistors, capacitors, inductors, transformers, relays, connectors, and printed circuit boards.

[0065] Currently, there are many types of transmission lines, which are widely used in many fields such as power, communications, and electronics.

[0066] Existing transmission lines include microstrip lines, striplines, and waveguides. Microstrip lines are suitable for the microwave frequency band, striplines are commonly used in high-speed digital circuits and microwave circuits, and waveguides are mainly used in the microwave and millimeter-wave frequency bands.

[0067] As a core component of electronic devices, integrated circuits interconnect the electronic components and transmission lines required by electronic devices. With the development of technology and the increase in market demand, electronic devices are constantly developing towards miniaturization, high performance, multi-functionality, and low power consumption, which drives the continuous progress of integrated circuit technology and gradually increases the operating frequency requirements of transmission lines.

[0068] Existing transmission lines commonly use micro-coaxial structures for high-frequency signal transmission. However, existing micro-coaxial structures are fabricated using a multi-layer electroplated copper process, which results in problems such as complex manufacturing processes, large height, structural instability, and poor high-frequency signal transmission quality.

[0069] In view of this, embodiments of this application provide a transmission line structure, such as... Figure 1 As shown, Figure 1 This is a cross-sectional schematic diagram of a transmission line structure provided in an embodiment of this application. The transmission line structure includes: a first substrate 101, a first shielding layer 102, a second substrate 103, and an inner conductor 104. The first substrate 101 is provided with a first through-hole, which penetrates the first substrate 101 in a direction perpendicular to the surface of the first substrate 101. The first shielding layer 102 is disposed on one side of the first substrate 101, covering the opening of the first through-hole on the first surface of the first substrate 101. The second substrate 103 is disposed on the side of the first substrate 101 away from the first shielding layer 102. The second substrate 103, the first through-hole, and the first shielding layer 102 form a cavity. The inner conductor 104 is located in the cavity, spaced apart from the first shielding layer 102, and insulated from each other.

[0070] The transmission line structure provided in this application embodiment has two aspects. First, the first via penetrates the first substrate 101. Therefore, in the direction perpendicular to the surface of the first substrate 101, the depth of the first via is the same as the thickness of the first substrate 101. Since the first substrate 101 can be easily and precisely processed to a very small thickness, such as 35 micrometers, 40 micrometers, or 50 micrometers, the depth of the first via can be precisely controlled to a very small size, ensuring the processing accuracy of the transmission line structure and thus achieving higher processing accuracy for the integrated circuit. Second, the first via, the first shielding layer 102, and the second substrate 103 can form a cavity to accommodate the inner conductor 104. The depth of the first via determines the thickness of the cavity, which in turn determines the thickness of the transmission line structure. By controlling the reduction of the thickness of the first substrate 101, the depth of the first via can be precisely controlled, thereby reducing the size of the transmission line structure and achieving a thinner and lighter integrated circuit.

[0071] Specifically, the first substrate 101 and the second substrate 103 can be made of materials such as silicon, gallium arsenide, sapphire, ceramics, polyimide, and polystyrene. The inner conductor 104 is mainly used for signal transmission, and its material can include: elemental metals and their alloys. Elemental metals include copper, silver, gold, aluminum, zinc, iron, tin, or platinum. Alloys include copper alloys, silver alloys, gold alloys, aluminum alloys, zinc alloys, iron alloys, tin alloys, platinum alloys, and other conductive materials. The first shielding layer 102 is spaced apart from the inner conductor 104 and insulated from it. It provides electromagnetic shielding for the side of the inner conductor 104 closest to the first shielding layer 102, ensuring the stability and reliability of signal transmission, reducing dissipation and radiation loss of the inner conductor 104 when transmitting high-frequency signals, thereby improving the transmission bandwidth of the transmission line structure. The first shielding layer 102 can be made of conductive materials, such as elemental metals and their alloys. Elemental metals include copper, silver, gold, aluminum, zinc, iron, tin, or platinum. Alloys include copper alloys, silver alloys, gold alloys, aluminum alloys, zinc alloys, iron alloys, tin alloys, platinum alloys, etc. This application does not impose any restrictions on the specific materials of the first substrate 101, the first shielding layer 102, the second substrate 103, and the inner conductor 104.

[0072] The second substrate 103, together with the first through-hole and the first shielding layer 102, forms a cavity enclosing the inner conductor 104. The second substrate 103 blocks the opening of the first through-hole on the surface of the first substrate 101 away from the first shielding layer 102, that is, the second substrate 103 at least covers the opening of the first through-hole on the side of the first shielding layer 102 away from the first plane. Figure 1 As shown, the second substrate 103 can be a plate-shaped structure, and the plate surface of the second substrate 103 can be directly fixed to the surface of the first substrate 101 away from the first shielding layer 102.

[0073] Or in another implementation, such as Figure 2As shown, the second substrate 103 is provided with a groove. In the direction perpendicular to the surface of the second substrate 103, the depth of the groove is less than the thickness of the second substrate 103, that is, the groove does not penetrate the second substrate 103. The second substrate 103 is fastened and fixed to the surface of the first substrate 101 away from the first shielding layer 102 through the surface of the plane where the groove opening is located. Thus, the groove of the second substrate 103, the first through hole and the first shielding layer 102 form a cavity for accommodating the inner conductor 104.

[0074] The transmission line structure also includes a support structure, which in some optional embodiments is disposed within the cavity and located between the inner conductor 104 and the first shielding layer 102. The support structure serves to support the inner conductor 104 while isolating the inner conductor 104 from the first shielding layer 102. The support structure needs to be made of an insulating material. Exemplarily, the material of the support structure includes at least one selected from silicon oxide, silicon nitride, silicon oxynitride, tantalum oxide, aluminum oxide, polyimide, benzocyclobutene, polybutylene terephthalate, acrylic adhesive, and epoxy resin. This application does not limit the specific material of the support structure.

[0075] The support structure may employ one or more support columns 301, which are spaced apart along the length of the inner conductor 104 and / or along the width of the inner conductor 104. In one example, such as... Figure 3 As shown, three support columns 301 are arranged between the inner conductor 104 and the first shielding layer 102, and are spaced apart along the length of the inner conductor 104 to provide stable support for the inner conductor 104. At the same time, they isolate the inner conductor 104 from the first shielding layer 102 to prevent the first shielding layer 102 from contacting the inner conductor 104, thus ensuring that the first shielding layer 102 has good electromagnetic shielding function.

[0076] In some alternative implementations, the inner conductor 104 is centrally positioned within the cavity to achieve good transmission performance and avoid performance degradation of the transmission line structure.

[0077] In some alternative embodiments, the support structure is disposed within the cavity and located between the inner conductor 104 and the second substrate 103. The support structure may employ one or more support pillars 301, which are spaced apart along the length extension direction of the inner conductor 104 and / or spaced apart along the width extension direction of the inner conductor 104.

[0078] In one example, such as Figure 4As shown, three support pillars 301 are arranged between the inner conductor 104 and the second substrate 103, and are spaced apart along the length of the inner conductor 104 to provide stable support for the inner conductor 104. It should be noted that there needs to be a certain distance between the inner conductor 104 and the first shielding layer 102 to ensure that the first shielding layer 102 has a good electromagnetic shielding function for the inner conductor 104.

[0079] In some alternative implementations, such as Figure 5 As shown, the transmission line structure also includes a second shielding layer 501; the second substrate 103 is provided with a second through hole, which penetrates the second substrate 103 along a direction perpendicular to the surface of the second substrate 103, and the second through hole communicates with the first through hole; the second shielding layer 501 is disposed on the side of the second substrate 103 away from the first substrate 101, covering the opening of the second through hole on the second surface of the second substrate 103, the second surface being the surface of the second substrate 103 away from the first substrate 101; the cavity is formed by the second shielding layer 501, the second through hole, the first through hole and the first shielding layer 102, and the inner conductor 104 is spaced apart from the second shielding layer 501 and insulated from each other.

[0080] The second shielding layer 501 is spaced apart from and insulated from the inner conductor 104, providing electromagnetic shielding to the side of the inner conductor 104 closest to the second shielding layer 501. This ensures the stability and reliability of signal transmission, reduces dissipation and radiation loss of the inner conductor 104 when transmitting high-frequency signals, and thus improves the transmission bandwidth of the transmission line structure. The second shielding layer 501 can be made of conductive materials, such as elemental metals and their alloys. Elemental metals include copper, silver, gold, aluminum, zinc, iron, tin, or platinum, and alloys include copper alloys, silver alloys, gold alloys, aluminum alloys, zinc alloys, iron alloys, tin alloys, platinum alloys, etc. This application does not limit the specific material of the second shielding layer 501.

[0081] In some alternative embodiments, the support structure is disposed within the cavity and located between the inner conductor 104 and the second shielding layer 501. The support structure may employ one or more support pillars 301, which are spaced apart along the length of the inner conductor 104 and / or spaced apart along the width of the inner conductor 104.

[0082] In one example, such as Figure 5 As shown, three support columns 301 are arranged between the inner conductor 104 and the second shielding layer 501, and are spaced apart along the length of the inner conductor 104 to provide stable support for the inner conductor 104. It should be noted that the inner conductor 104 needs to have a certain distance from the first shielding layer 102 and the second shielding layer 501 to ensure that the first shielding layer 102 and the second shielding layer 501 have good electromagnetic shielding function for the inner conductor 104.

[0083] In some alternative implementations, such as Figure 6 As shown, the transmission line structure also includes a third shielding layer 601 and a fourth shielding layer 602. The third shielding layer 601 at least covers the sidewall of the first through-hole and the third surface of the first substrate 101 away from the first shielding layer 102, with the third surface opposite to the first surface. The fourth shielding layer 602 at least covers the sidewall of the second through-hole and the fourth surface of the second substrate 103 away from the second shielding layer 501, with the fourth surface opposite to the second surface. The cavity is formed by the second shielding layer 501, the fourth shielding layer 602 of the second through-hole, the third shielding layer 601 of the first through-hole, and the first shielding layer 102. The inner conductor 104 is spaced apart from the third shielding layer 601 and the fourth shielding layer 602 and is insulated from each other.

[0084] The first shielding layer 102, the second shielding layer 501, the third shielding layer 601, and the fourth shielding layer 602 form a shielding cover within the cavity, providing excellent electromagnetic shielding for the inner conductor 104.

[0085] In a direction perpendicular to the first surface of the first substrate 101, the thickness of the first shielding layer 102 is 5 to 100 micrometers. For example, the thickness of the first shielding layer 102 is 5 micrometers, 6 micrometers, 8 micrometers, or 10 micrometers, etc., and is not limited here.

[0086] The thickness of the second shielding layer 501 is 5 to 100 micrometers in a direction perpendicular to the second surface of the second substrate 103. For example, the thickness of the second shielding layer 501 is 5 micrometers, 6 micrometers, 8 micrometers, or 10 micrometers, etc., and is not limited here.

[0087] In the direction perpendicular to the inner wall of the first through hole, the thickness of the third shielding layer 601 is 0.5 to 10 micrometers. For example, the thickness of the third shielding layer 601 can be 0.5 micrometers, 1 micrometer, 2 micrometers, 4 micrometers, 6 micrometers, 8 micrometers, or 10 micrometers, etc., and is not limited here.

[0088] In the direction perpendicular to the inner wall of the second through hole, the thickness of the fourth shielding layer 602 is 0.5 to 10 micrometers. For example, the thickness of the fourth shielding layer 602 can be 0.5 micrometers, 1 micrometer, 2 micrometers, 4 micrometers, 6 micrometers, 8 micrometers, or 10 micrometers, etc., and is not limited here.

[0089] In some alternative embodiments, the thickness of the first shielding layer 102 in the direction perpendicular to the surface of the first substrate 101 is greater than the thickness of the third shielding layer 601 in the direction perpendicular to the sidewall of the first through hole. It is understood that, supported by the inner wall of the first through hole, the third shielding layer 601 can be thinner than the first shielding layer 102, thus ensuring the shielding function while reducing manufacturing costs.

[0090] The thickness of the second shielding layer 501 in the direction perpendicular to the surface of the second substrate 103 is greater than the thickness of the fourth shielding layer 602 in the direction perpendicular to the sidewall of the second through hole. It is understood that, with the support of the inner wall of the second through hole, the fourth shielding layer 602 can be made thinner than the second shielding layer 501, thus ensuring the shielding function while reducing manufacturing costs.

[0091] In some optional embodiments, in the direction perpendicular to the surface of the first substrate 101, the distance between the first shielding layer 102 and the second shielding layer 501 is equal to the distance between the first surface and the second surface. The distance between the first shielding layer 102 and the second shielding layer 501 in the direction perpendicular to the surface of the first substrate 101 determines the height of the cavity. By grinding and thinning the first substrate 101 and the second substrate 103, the heights of the first and second vias can be precisely controlled. By controlling the processing parameters of the third shielding layer 601 and the fourth shielding layer 602, the distance between the first surface of the first substrate 101 and the second surface of the second substrate 103 on the formed cavity can be controlled, thereby achieving precise control of the cavity dimensions and ensuring the stability of the signal transmission capability of the transmission line structure.

[0092] Existing microcoaxial structures are multilayer copper structures formed on wafers through surface micromachining (photolithography, electroplating, CMP, etc.). These structures suffer from drawbacks such as complex processes, large copper structure height due to multilayer copper stacking, structural instability, and high cost. The cavities in existing microcoaxial structures used to house the inner conductor 104 are typically larger than 200 micrometers, and are suitable for operating frequencies below 300 GHz. The transmission line structure provided in this application, by thinning the first substrate 101 and the second substrate 103 to a predetermined size, can form a cavity with a height of less than 100 micrometers, and proportionally reduce the cavity width and the size of the inner conductor 104, enabling the transmission of high-frequency signals above 600 GHz.

[0093] The distance between the first shielding layer 102 and the second shielding layer 501 is determined by the height of the first substrate 101 and the second substrate 103, and therefore can be precisely controlled. In one example, the distance between the first shielding layer 102 and the second shielding layer 501 is 60 to 600 micrometers. For example, the distance between the first shielding layer 102 and the second shielding layer 501 can be 60 micrometers, 65 micrometers, 70 micrometers, 75 micrometers, 80 micrometers, 85 micrometers, 90 micrometers, 95 micrometers, 100 micrometers, 110 micrometers, 120 micrometers, 150 micrometers, 180 micrometers, 200 micrometers, 300 micrometers, 400 micrometers, 500 micrometers, or 600 micrometers, etc., and is not limited here.

[0094] For example, still as Figure 6As shown, during the processing, the height h1 of the first substrate 101 and the height h2 of the second substrate 103 are respectively processed to 38 micrometers. The height of the third shielding layer 601 and the height of the fourth shielding layer 602 are controlled to 1 micrometer through electroplating. After the first substrate 101 and the second substrate 103 are fastened and fixed by bonding process, the third shielding layer 601 covering the third surface of the first substrate 101 and the fourth shielding layer 602 covering the fourth surface of the first substrate 101 are sandwiched between the third surface of the first substrate 101 and the fourth surface of the second substrate 103, so that the distance between the bonding point of the first substrate 101 and the second substrate 103, that is, the distance between the third surface and the fourth surface, does not exceed 2 micrometers, so that the distance between the first surface and the second surface is close to 80 micrometers, thereby controlling the distance h3 between the first shielding layer 102 and the second shielding layer 501 to be close to 80 micrometers, realizing the transmission of high frequency signals above 600 GHz.

[0095] It is understandable that, due to the possibility of precision errors in the processing, the limitations on the thickness of the first shielding layer 102, the second shielding layer 501, the third shielding layer 601, and the fourth shielding layer 602, as well as the limitation on the distance between the first shielding layer 102 and the second shielding layer 501, in the above embodiments have a reasonable range of error, as understood by those skilled in the art.

[0096] In some alternative implementations, such as Figure 7 As shown, the first substrate 101 has a groove on the side away from the second substrate 103. The groove communicates with a first through-hole in a direction perpendicular to the first surface. The first shielding layer 102 at least covers the groove. The opening of the first through-hole is located within the region of the opening of the groove in the orthographic projection of the first shielding layer 102. In this structure, the distance between the first surface of the first substrate 101 and the second surface of the second substrate 103 is greater than the distance between the first shielding layer 102 and the second shielding layer 501. The first surface of the first substrate 101 is not completely covered by the first shielding layer 102, and the second surface of the second substrate 103 is not completely covered by the second shielding layer 501. The thicknesses of the first substrate 101 and the second substrate 103 are relatively thicker, making the overall transmission line structure more robust.

[0097] It is understood that the third shielding layer 601 can also cover the side of the first shielding layer 102 near the inner conductor 104. Therefore, in some optional embodiments, the support structure is disposed within the cavity and located between the inner conductor 104 and the third shielding layer 601 covering the side of the first shielding layer 102 near the inner conductor 104. The support structure may employ one or more support pillars 301, which are spaced apart along the length extension direction of the inner conductor 104 and / or spaced apart along the width extension direction of the inner conductor 104.

[0098] In one example, such as Figure 6 As shown, three support columns 301 are arranged between the inner conductor 104 and the third shielding layer 601 covering the first shielding layer 102 on the side close to the inner conductor 104, and are spaced apart along the length of the inner conductor 104 to provide stable support for the inner conductor 104. It should be noted that there needs to be a certain distance between the inner conductor 104 and the third shielding layer 601 to ensure that the third shielding layer 601 has a good electromagnetic shielding function for the inner conductor 104.

[0099] It is understandable that the fourth shielding layer 602 can also cover the side of the second shielding layer 501 closest to the inner conductor 104; therefore, in another example, such as Figure 7 As shown, three support columns 301 are arranged between the inner conductor 104 and the fourth shielding layer 602 covering the second shielding layer 501 on the side near the inner conductor 104, and are spaced apart along the length of the inner conductor 104 to provide stable support for the inner conductor 104. It should be noted that there needs to be a certain distance between the inner conductor 104 and the fourth shielding layer 602 to ensure that the fourth shielding layer 602 has a good electromagnetic shielding function for the inner conductor 104.

[0100] In some optional embodiments, the angle between the sidewall busbar of the first through hole and the first shielding layer 102 is 90° to 95°. For example, the angle between the sidewall busbar of the first through hole and the first shielding layer 102 is 90°, 91°, 92°, 93°, 94° or 95°.

[0101] Based on the same inventive concept, this application also provides a method for preparing a transmission line structure. It should be noted that the basic principle and technical effects of the method for preparing a transmission line structure provided in this application are the same as those in the above embodiments. For the sake of brevity, any parts not mentioned in this application can be referred to the corresponding content in the above embodiments.

[0102] See also Figure 8 The method provided in this application includes:

[0103] S801, providing a first substrate 101 and a second substrate 103;

[0104] S802, A first shielding layer 102 is formed on one side of the first substrate 101;

[0105] S803, A first through hole is formed through the first substrate 101 in a direction perpendicular to the surface of the first substrate 101, so that the first shielding layer 102 covers the opening of the first through hole on the first surface of the first substrate 101;

[0106] S804, Form an inner conductor 104 that is spaced apart from and insulated from the first shielding layer 102;

[0107] S805, the second substrate 103 is bonded to the side of the first substrate 101 away from the first shielding layer 102, so that the second substrate 103, the first via and the first shielding layer 102 form a cavity surrounding the inner conductor 104, and a transmission line structure is obtained.

[0108] The transmission line structure fabrication method provided in this application has two aspects. First, the first via penetrates the first substrate 101. Therefore, in the direction perpendicular to the surface of the first substrate 101, the depth of the first via is the same as the thickness of the first substrate 101. Since the first substrate 101 can be easily and precisely processed to a very small thickness, such as 35 micrometers, 40 micrometers, or 50 micrometers, the depth of the first via can be precisely controlled to a very small size, ensuring the processing accuracy of the transmission line structure and thus achieving higher processing accuracy for integrated circuits. Second, the first via, the first shielding layer 102, and the second substrate 103 can form a cavity to accommodate the inner conductor 104. The depth of the first via determines the thickness of the cavity, which in turn determines the thickness of the transmission line structure. By controlling the reduction of the thickness of the first substrate 101, the depth of the first via can be precisely controlled, thereby reducing the size of the transmission line structure and achieving thinner and lighter integrated circuits.

[0109] In some alternative implementations, the method further includes:

[0110] A second shielding layer 501 is formed on one side of the second substrate 103;

[0111] A second through-hole is formed through the second substrate 103 in a direction perpendicular to the surface of the second substrate 103, so that the second shielding layer 501 covers the opening of the second through-hole on the second surface of the second substrate 103;

[0112] The second substrate 103 is bonded to the side of the first substrate 101 away from the first shielding layer 102, so that the second substrate 103, the first via, and the first shielding layer 102 form a cavity, including:

[0113] The side of the second substrate 103 away from the second shielding layer 501 is bonded to the side of the first substrate 101 away from the first shielding layer 102, so that the second through hole is connected to the first through hole, and the second shielding layer 501, the second through hole, the first through hole and the first shielding layer 102 form a cavity surrounding the inner conductor 104, wherein the inner conductor 104 and the second shielding layer 501 are spaced apart and insulated from each other.

[0114] The method provided in the above embodiments can be used to prepare the above embodiments and appendices. Figures 2 to 7 The provided transmission line structure.

[0115] In some alternative implementations, the method further includes:

[0116] A third shielding layer 601 is formed on the sidewall of the first through hole and on the third surface of the first substrate 101 away from the first shielding layer 102, with the third surface being disposed opposite to the first surface;

[0117] A fourth shielding layer 602 is formed on the sidewall of the second through hole and on the fourth surface of the second substrate 103 away from the second shielding layer 501, with the fourth surface being disposed opposite to the second surface.

[0118] In the above operation, the side of the second substrate 103 away from the second shielding layer 501 is bonded to the side of the first substrate 101 away from the first shielding layer 102, so that the second through-hole communicates with the first through-hole. The second shielding layer 501, the second through-hole, the first through-hole, and the first shielding layer 102 form a cavity enclosing the inner conductor 104, including:

[0119] The side of the second substrate 103 away from the second shielding layer 501 is fastened to the side of the first substrate 101 away from the first shielding layer 102, and the third shielding layer 601 on the surface of the first substrate 101 is bonded to the fourth shielding layer 602 on the surface of the second substrate 103, so that the second shielding layer 501, the fourth shielding layer 602 of the second through hole, the third shielding layer 601 of the first through hole and the first shielding layer 102 form a cavity surrounding the inner conductor 104, wherein the inner conductor 104 is spaced apart from the third shielding layer 601 and the fourth shielding layer 602 and is mutually insulated.

[0120] The method provided in the above embodiments can be used to prepare the above embodiments and appendices. Figure 6 Or the transmission line structure provided by 7.

[0121] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be implemented independently or in combination with each other. The same or similar concepts or processes may not be described again in some embodiments.

[0122] The first step is to select a first wafer 901 and a second wafer 1001 with appropriate thicknesses. The thicknesses of the first wafer 901 and the second wafer 1001 are between 100 and 1000 micrometers, respectively. The thicknesses of the first wafer 901 and the second wafer 1001 can be the same or different.

[0123] The second step is Figure 9As shown in Figure a, a seed layer is deposited on the bottom surface of the first wafer 901 shown in Figure a, and then electroplated to form the first shielding layer 902 shown in Figure b. The first shielding layer 902 also serves as a support structure 905 for supporting the inner conductor 906. A first via 903, shown in Figure c, is etched into the first wafer 901, penetrating the first wafer 901 in a direction perpendicular to the top surface. A third shielding layer 904 is formed on the inner wall of the first via 903 and the surface of the top surface of the first wafer 901 by sputtering, deposition, or electroplating. Then, the support structure 905 shown in Figure d is prepared on the first shielding layer 902 using conventional processes. The support structure 905 is periodically and uniformly or non-uniformly arranged in the groove formed by the first via 903 and the first shielding layer 902. Finally, the inner conductor 906 shown in Figure e is formed on the support structure 905 by processes such as printing, deposition, and electroplating.

[0124] The third step, such as Figure 10 As shown in Figure a, a seed layer is deposited on the top surface of the second wafer 1001 shown in Figure a and electroplated to form the second shielding layer 1002 shown in Figure b. A second via 1003 shown in Figure c, penetrating the second wafer 1001 in a direction perpendicular to the top surface, is etched on the second wafer 1001. A fourth shielding layer 1004 is formed on the surface of the second via 1003 and the bottom surface of the second wafer 1001 by sputtering, deposition or electroplating processes.

[0125] Step four, as Figure 11 As shown in Figure a, the first wafer 901 and the second wafer 1001 shown in Figure a are bonded together to form the cavity 1101 of the micro-coaxial structure shown in Figure b, resulting in the transmission line structure shown in Figure c, in which the inner conductor 906 is centrally arranged in the cavity 1101.

[0126] This embodiment utilizes bulk silicon technology and bonding of two wafers to form a microcoaxial closed structure. An outer shielding layer is formed by depositing copper metal, while the microcoaxial structure is located inside the wafer, making the microcoaxial structure more stable, reducing process complexity, and lowering costs.

[0127] In one example, such as Figure 12 As shown, the second step of depositing a seed layer and electroplating to form the first shielding layer 902 on the bottom surface of the first wafer 901 specifically includes: etching a groove on the bottom of the first wafer 901, depositing the seed layer in the groove, then fabricating a shielding material layer, and polishing the shielding material layer flat to form the recessed first shielding layer 902. The second shielding layer 1002 of the second wafer 1001 can also be prepared using the above operation. Enclosing the first shielding layer 902 within the groove protects the first shielding layer 902 while making the transmission line structure more robust and stable.

[0128] Based on the same inventive concept, embodiments of this application also provide a transmission cable, which may include N or more transmission line structures as described in the first aspect, where N is a positive integer greater than or equal to 1. The transmission cable may be a PCIe (Peripheral Component Interconnect Express) cable, an MCIO (Multi-Channel Input / Output) cable, a flat cable, etc. This application does not limit the specific type and application of the transmission cable.

[0129] In some optional implementations, N is a positive integer greater than or equal to 3, and the transmission line structure with more than N lines includes one first transmission line and at least two second transmission lines, with at least one end of the first transmission line connected to at least two second transmission lines respectively. The first transmission line can serve as a backbone, and the at least two second transmission lines can serve as branches of the backbone.

[0130] Based on the same inventive concept, embodiments of this application also provide an electronic device, such as... Figure 13 As shown, the electronic device includes a substrate 1301, M electronic devices 1302, and a transmission line structure 1303 of the first aspect, where M is a positive integer greater than or equal to 1.

[0131] Electronic devices 1302 and transmission line structures 1303 can be disposed on substrate 1301, and electronic devices 1302 can be interconnected through transmission line structures 1303. Each electronic device 1302 can be connected to other external devices 1304 or components through the transmission line structure 1303. Alternatively, when an electronic device includes multiple electronic devices 1302, different electronic devices 1302 can also be connected through transmission line structures 1303.

[0132] Electronic devices can be smartphones, tablets, smart TV game consoles, autonomous driving systems, in-vehicle infotainment systems, medical devices, programmable logic controllers, robots, sensors, satellite electronic equipment, base stations, servers, etc. This application does not limit the specific type of electronic device.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0134] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

Claims

1. A transmission line structure, characterized in that: include: A first substrate, a first shielding layer, a second substrate, and an inner conductor; The first substrate is provided with a first through hole, and the first through hole penetrates the first substrate in a direction perpendicular to the surface of the first substrate; The first shielding layer is disposed on one side of the first substrate, covering an opening of the first through hole on the first surface of the first substrate; The second substrate is arranged at a side of the first substrate away from the first shielding layer, and the second substrate, the first through hole and the first shielding layer form a cavity; The inner conductor is located in the cavity, spaced apart from the first shielding layer, and insulated from each other.

2. The transmission line structure according to claim 1, characterized in that Also comprising a second shielding layer; The second substrate is provided with a second through hole, the second through hole penetrates the second substrate in a direction perpendicular to the surface of the second substrate, and the second through hole is connected with the first through hole; The second shielding layer is arranged on a side of the second substrate away from the first substrate, covering an opening of the second through hole on a second surface of the second substrate, where the second surface is a surface of the second substrate away from the first substrate; The cavity is formed by the second shielding layer, the second through hole, the first through hole and the first shielding layer, and the inner conductor and the second shielding layer are spaced apart and insulated from each other.

3. The transmission line structure according to claim 2, characterized in that It also includes a third shielding layer and a fourth shielding layer, the third shielding layer at least covers the side wall of the first through hole and the third surface of the first substrate away from the first shielding layer, the third surface is arranged opposite to the first surface, the fourth shielding layer at least covers the side wall of the second through hole and the fourth surface of the second substrate away from the second shielding layer, the fourth surface is arranged opposite to the second surface, the cavity is formed by the second shielding layer, the fourth shielding layer of the second through hole, the third shielding layer of the first through hole and the first shielding layer, the inner conductor is spaced apart from the third shielding layer and the fourth shielding layer and is insulated from each other.

4. The transmission line structure according to claim 3, characterized in that The thickness of the first shielding layer in a direction perpendicular to the surface of the first substrate is greater than the thickness of the third shielding layer in a direction perpendicular to the side wall of the first through hole; the thickness of the second shielding layer in a direction perpendicular to the surface of the second substrate is greater than the thickness of the fourth shielding layer in a direction perpendicular to the side wall of the second through hole.

5. The transmission line structure according to claim 2, characterized in that: In a direction perpendicular to the first substrate surface, a distance between the first shielding layer and the second shielding layer is equal to a distance between the first surface and the second surface.

6. The transmission line structure according to claim 2, characterized in that It also includes a supporting structure, which is arranged in the cavity and located between the inner conductor and the first shielding layer.

7. The transmission line structure according to claim 1, characterized in that The first substrate has a groove on a side away from the second substrate, the groove is connected to the first through hole in a direction perpendicular to the first surface, the first shielding layer at least covers the groove, and the opening of the first through hole is located on the orthographic projection of the first shielding layer, within the area of ​​the opening of the groove on the orthographic projection of the first shielding layer.

8. A method for preparing a transmission line structure, characterized in that: include: providing a first substrate and a second substrate; forming a first shielding layer on one side of the first substrate; forming a first through hole penetrating the first substrate in a direction perpendicular to the surface of the first substrate, so that the first shielding layer covers an opening of the first through hole on the first surface of the first substrate; forming an inner conductor spaced apart from the first shielding layer and insulated from each other; The second substrate is bonded to a side of the first substrate away from the first shielding layer, so that the second substrate, the first through hole and the first shielding layer form a cavity enclosing the inner conductor, thereby obtaining a transmission line structure.

9. The method for preparing a transmission line structure according to claim 8, characterized in that: Also includes: forming a second shielding layer on one side of the second substrate; forming a second through hole penetrating the second substrate in a direction perpendicular to the surface of the second substrate, so that the second shielding layer covers an opening of the second through hole on the second surface of the second substrate; The step of bonding the second substrate to a side of the first substrate away from the first shielding layer so that the second substrate, the first through hole and the first shielding layer form a cavity comprises: Bond a side of the second substrate away from the second shielding layer to a side of the first substrate away from the first shielding layer, so that the second through hole is connected to the first through hole, and the second shielding layer, the second through hole, the first through hole and the first shielding layer form a cavity enclosing the inner conductor, wherein the inner conductor and the second shielding layer are spaced apart and insulated from each other.

10. The method for preparing a transmission line structure according to claim 9, characterized in that: Also includes: forming a third shielding layer on the sidewall of the first through hole and a third surface of the first substrate away from the first shielding layer, wherein the third surface is arranged opposite to the first surface; forming a fourth shielding layer on the sidewall of the second through hole and a fourth surface of the second substrate away from the second shielding layer, wherein the fourth surface is arranged opposite to the second surface; The step of bonding the side of the second substrate away from the second shielding layer to the side of the first substrate away from the first shielding layer, so that the second through hole is connected to the first through hole, and the second shielding layer, the second through hole, the first through hole and the first shielding layer form a cavity enclosing the inner conductor, comprises: The side of the second substrate away from the second shielding layer is buckled with the side of the first substrate away from the first shielding layer, and the third shielding layer on the surface of the first substrate is bonded with the fourth shielding layer on the surface of the second substrate, so that the second shielding layer, the fourth shielding layer of the second through hole, the third shielding layer of the first through hole and the first shielding layer form a cavity enclosing the inner conductor, wherein the inner conductor is spaced apart from the third shielding layer and the fourth shielding layer and are insulated from each other.

Images