Ceramic packaging base and crystal oscillator

Abstract

The utility model relates to the technical field of semiconductors, in particular to a ceramic packaging base and a crystal oscillator, and the ceramic packaging base comprises a single-layer ceramic base and a kovar ring. The kovar ring is arranged on the surface of the single-layer ceramic base, and an accommodating cavity is defined by the kovar ring and the single-layer ceramic base; an electrode bonding pad and a first through hole are arranged on the surface of the single-layer ceramic base in the accommodating cavity; a conductive structure of which the extending direction is vertical to the single-layer ceramic base is arranged in the first through hole; a metal wire is further arranged on the surface of the single-layer ceramic base, one end of the metal wire is connected with the electrode bonding pad, and the other end of the metal wire is connected with the conductive structure; the width of the metal wire is smaller than or equal to the diameter of the first through hole. According to the embodiment of the invention, the production process can be simplified, the packaging reliability and long-term stability are improved, in addition, the consumption of precious metal can be reduced, and the production cost is effectively reduced.

Description

A ceramic packaging substrate and crystal oscillator Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically, to a ceramic packaging substrate and a crystal oscillator. Background Technology

[0002] In the field of semiconductor packaging, traditional ceramic packaging substrates typically rely on multilayer sintering processes to achieve their conductivity and support functions. This traditional method not only involves complex manufacturing processes, including multiple lamination, alignment, and high-temperature sintering steps, which significantly increases the overall process complexity, but also leads to a substantial increase in material and production costs due to the use of various different materials and complex processing steps.

[0003] Furthermore, poor interlayer bonding is particularly prominent in multilayer structures, directly leading to instability in electrical connections. This manifests as frequent changes in contact resistance and even open circuits. More seriously, interlayer bonding defects can easily cause gas leakage in the package, severely affecting the stability of the internal environment and ultimately reducing the overall reliability of the device.

[0004] Furthermore, in existing technologies, in order to form the necessary conductive structure within the ceramic substrate, it is often necessary to deposit large amounts of precious metal materials (such as gold and silver) through processes such as printing. Although this method can meet the electrical performance requirements, the high cost of the precious metal materials themselves greatly increases the manufacturing cost. Summary of the Invention

[0005] The purpose of this application is to provide a ceramic packaging substrate and crystal oscillator, which can simplify the production process, improve packaging reliability and long-term stability. In addition, this application can reduce the amount of precious metals used and effectively reduce production costs.

[0006] The embodiments of this application are implemented as follows:

[0007] In a first aspect, embodiments of this application provide a ceramic packaging substrate, including a single-layer ceramic substrate and a Kovar ring; the Kovar ring is disposed on the surface of the single-layer ceramic substrate, and the Kovar ring and the single-layer ceramic substrate form a receiving cavity; an electrode pad and a first through hole are provided on the surface of the single-layer ceramic substrate within the receiving cavity; a conductive structure extending perpendicularly to the single-layer ceramic substrate is provided in the first through hole; a metal wire is also provided on the surface of the single-layer ceramic substrate, one end of the metal wire is connected to the electrode pad, and the other end is connected to the conductive structure; the width of the metal wire is less than or equal to the diameter of the first through hole.

[0008] As an optional implementation, the Kovar ring has a first inner wall surface and a second inner wall surface that are parallel to each other; the electrode pad is close to the first inner wall surface of the Kovar ring, and the first through hole is close to the second inner wall surface of the electrode pad.

[0009] As an optional implementation, the metal wire is arranged in a direction perpendicular to the inner wall surface of the first side.

[0010] As an optional implementation, there are two electrode pads near the inner wall of the first side, and the two electrode pads are sequentially covered with a nickel plating layer and a gold plating layer.

[0011] As an optional implementation, the single-layer ceramic base has four bottom electrodes on the surface opposite to the Kovar ring; the single-layer ceramic base has a rectangular structure; and the four bottom electrodes are respectively located at the four corners of the single-layer ceramic base.

[0012] As an optional implementation, the first bottom electrode is connected to the end of the conductive structure away from the metal wire; the second bottom electrode and the third bottom electrode are arranged diagonally and connected by a back metal connecting wire.

[0013] As an optional implementation, the fourth bottom electrode and the electrode pad away from the metal line have a projected overlap area; the single-layer ceramic base is provided with a second through hole in the projected overlap area; the conductive structure is provided in the second through hole for connecting the fourth bottom electrode and the electrode pad.

[0014] As an optional implementation, the conductive structure includes a conductive paste filling the first through hole.

[0015] As an optional implementation, the electrode pad includes a bottom base disposed on a monolayer ceramic substrate and a crystal support disposed on the bottom base; the projection of the bottom base on the monolayer ceramic substrate covers the crystal support.

[0016] Secondly, embodiments of this application provide a crystal oscillator, including a quartz crystal, a package cover plate, and the aforementioned ceramic package base; the quartz crystal is connected to the electrode pads through a conductive silver paste layer; the package cover plate is disposed on the surface of the Kovar ring away from the single-layer ceramic base, for sealing the accommodating cavity.

[0017] The beneficial effects of the embodiments of this application include:

[0018] This application embodiment employs a single-layer ceramic base, unlike traditional multi-layer structures. The single-layer ceramic base consists of only a single ceramic layer, eliminating the need for multiple lamination, alignment, and high-temperature co-firing processes. This application embodiment limits the width of the metal wire to no more than the diameter of the through-hole, thereby controlling the projected area of ​​the metal wire on the single-layer ceramic base and significantly reducing the amount of precious metals used. Therefore, this application embodiment can reduce costs while ensuring performance, significantly reducing material costs while meeting electrical connection requirements, without compromising connection reliability.

[0019] The crystal oscillator provided in this application includes the above-mentioned ceramic packaging base, which can not only simplify the production process, improve packaging reliability and long-term stability, but also reduce the amount of precious metals used, effectively reducing production costs. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 is a schematic diagram of the structure of a ceramic encapsulation base according to an embodiment of this application;

[0022] Figure 2 is a second schematic diagram of the structure of the ceramic packaging base according to an embodiment of this application;

[0023] Figure 3 is a third schematic diagram of the structure of the ceramic encapsulation base according to an embodiment of this application.

[0024] Icons: 100-Single-layer ceramic base; 101-Kovar ring; 102-Accommodation cavity; 103-Electrode pad; 104-First through hole; 105-Conductive structure; 106-Metal wire; 107-First side inner wall surface; 108-Second side inner wall surface; 109-Bottom electrode; 110-Back metal connection line; 111-Bottom base; 112-Crystal support. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0029] In the field of semiconductor packaging, traditional ceramic packaging substrates typically rely on multilayer sintering processes to achieve their conductivity and support functions. This traditional method not only involves complex manufacturing processes, including multiple lamination, alignment, and high-temperature sintering steps, which significantly increases the overall process complexity, but also leads to a substantial increase in material and production costs due to the use of various different materials and complex processing steps.

[0030] Furthermore, poor interlayer bonding is particularly prominent in multilayer structures, directly leading to instability in electrical connections. This manifests as frequent changes in contact resistance and even open circuits. More seriously, interlayer bonding defects can easily cause gas leakage in the package, severely affecting the stability of the internal environment and ultimately reducing the overall reliability of the device.

[0031] Furthermore, in existing technologies, in order to form the necessary conductive structure within the ceramic substrate, it is often necessary to deposit large amounts of precious metal materials (such as gold and silver) through processes such as printing. Although this method can meet the electrical performance requirements, the high cost of the precious metal materials themselves greatly increases the manufacturing cost.

[0032] To address the aforementioned technical problems, embodiments of this application provide a ceramic packaging substrate and a crystal oscillator.

[0033] Referring to Figures 1, 2, and 3, this application embodiment provides a ceramic packaging substrate, including a single-layer ceramic substrate 100 and a Kovar ring 101. The Kovar ring 101 is disposed on the surface of the single-layer ceramic substrate 100, and the Kovar ring 101 and the single-layer ceramic substrate 100 form a receiving cavity 102. Electrode pads 103 and a first through hole 104 are provided on the surface of the single-layer ceramic substrate 100 within the receiving cavity 102. A conductive structure 105 extending perpendicularly to the single-layer ceramic substrate 100 is provided in the first through hole 104. A metal wire 106 is also provided on the surface of the single-layer ceramic substrate 106, one end of which is connected to the electrode pad 103, and the other end is connected to the conductive structure 105. The width of the metal wire 106 is less than or equal to the diameter of the first through hole 104.

[0034] The conductive structure 105 includes a conductive paste filled within the first through-hole 104. Alternatively, a conductive post can be directly disposed within the first through-hole 104 if necessary, allowing the metal wire 106 to be directly connected to the metal post.

[0035] The ceramic packaging base provided in this application embodiment solves the problems of complex multilayer sintering process, high cost and poor reliability in the prior art by adopting a single-layer ceramic base 100 combined with Kovar ring 101 structure and conductive structure 105 in the first through hole 104 connected to metal wire 106.

[0036] The embodiments of this application adopt a single-layer ceramic base 100, which is different from the traditional multi-layer structure. The single-layer ceramic base 100 is composed of only a single ceramic layer and does not require multiple lamination, alignment and high-temperature co-firing processes.

[0037] Specifically, it has the following technical effects:

[0038] The embodiments of this application can eliminate the processes of lamination, alignment, and interlayer conduction, thereby reducing equipment investment and labor costs; therefore, the embodiments of this application can simplify the manufacturing process.

[0039] This application embodiment eliminates the use of multi-layer green ceramic tape, intermediate adhesive, and other materials, directly saving raw material costs; therefore, this application embodiment can reduce the types and amounts of materials used.

[0040] The embodiments of this application can avoid interlayer defects, eliminate problems such as unstable contact resistance, open circuit, and air leakage caused by poor interlayer bonding, and improve the long-term stability of the device.

[0041] Regarding the Kovar ring 101, in this embodiment, a Kovar ring 101 is disposed on the surface of a single-layer ceramic substrate 100, which, together with the ceramic substrate, forms an accommodating cavity 102 for accommodating wafers or other electronic components. The Kovar ring 101 is used for a sealing connection between the ceramic and the metal. The Kovar ring 101 helps to enhance the structural sealing performance. After co-firing with the ceramic, the Kovar ring 101 has good thermal compatibility and sealing performance, effectively preventing gas leakage in the encapsulation.

[0042] Regarding the description of the first through hole 104 and the conductive structure 105, in this embodiment of the application, a first through hole 104 is formed vertically through a single-layer ceramic base 100, and the hole is filled with conductive material to form a conductive structure 105. The extension direction of the conductive structure 105 is perpendicular to the plane of the base.

[0043] It should be noted that the above configuration enables electrical conductivity between the upper and lower surfaces of the single-layer ceramic substrate 100. By replacing traditional interlayer wiring with paste-filled holes, reliable signal transmission is ensured. This embodiment improves conductivity stability; the conductive structure 105 is integrally sintered with the ceramic substrate, resulting in a strong bond and avoiding the problem of traditional printed circuit boards detaching due to thermal stress. Furthermore, different conductive pastes such as silver paste and copper paste can be selected according to requirements, balancing performance and cost.

[0044] In this embodiment, a metal wire 106 is arranged on the surface of a ceramic substrate, with one end connected to an electrode pad 103 and the other end connected to a conductive structure 105. The width of the metal wire 106 is less than or equal to the diameter of the first through hole 104. It should be noted that the metal wire 106 in this embodiment has a uniform width along its extension path, and the width of the end of the metal wire 106 connected to the conductive structure 105 is also uniform.

[0045] The above setup has the following technical effects:

[0046] The embodiments of this application can achieve local fine wiring: the metal line 106 is used to connect the electrode pad 103 and the conductive structure to meet the requirements of complex circuit layout.

[0047] This application embodiment can control the amount of precious metals used: by limiting the width of the metal wire 106 to no more than the diameter of the through hole, its projected area on the single-layer ceramic base 100 is controlled, significantly reducing the amount of precious metals (such as gold and silver) used. Therefore, this application embodiment can reduce costs while ensuring performance, significantly reducing material costs while meeting electrical connection requirements, without affecting connection reliability.

[0048] Referring to Figures 1 and 2, in an optional embodiment, the Kovar ring 101 has a first inner wall surface 107 and a second inner wall surface 108 that are parallel to each other; the electrode pad 103 is close to the first inner wall surface 107 of the Kovar ring 101, and the first through hole 104 is close to the second inner wall surface 108 of the electrode pad 103.

[0049] In this embodiment, the electrode pads 103 are positioned close to the inner wall 107 of the first side of the Kovar ring 101. This arrangement helps to reduce the signal transmission path length, lower impedance, and improve the efficiency of electrical signal transmission.

[0050] In this embodiment, the first through-hole 104 is located near the second inner wall surface 108 of the electrode pad 103, and the first through-hole 104 is located on the side of the electrode pad 103 near its second inner wall surface 108. This design ensures that the conductive structure 105 can effectively pass through the single-layer ceramic substrate 100 to achieve electrical conduction between the upper and lower surfaces, while minimizing unnecessary line extensions, thereby saving precious metal materials and simplifying the manufacturing process.

[0051] The technical effects that the embodiments of this application can produce are as follows:

[0052] Firstly, the embodiments of this application can optimize space utilization. By reasonably arranging the positions of the electrode pads 103 and the first through hole 104, the space inside the entire accommodating cavity 102 can be fully utilized, which not only ensures the functional realization of each component, but also avoids unnecessary space waste.

[0053] Secondly, the embodiments of this application can enhance electrical performance, shorten the distance from electrode pad 103 to the first through hole 104, reduce the influence of resistance and inductance, and improve the overall circuit response speed and stability.

[0054] In high-frequency crystal oscillators or radio frequency modules, this layout in the embodiments of this application can significantly reduce signal interference and improve the operating frequency range and signal quality of the device. Meanwhile, due to the use of a single-layer ceramic substrate 100 and an optimized layout of the electrode pads 103 and the first through-hole 104, this design is particularly suitable for the packaging requirements of miniaturized, high-performance electronic devices, meeting both the size requirements of modern electronic products and ensuring excellent electrical performance.

[0055] Referring to FIG1, as an optional embodiment, the metal wire 106 is arranged along a direction perpendicular to the first side inner wall surface 107.

[0056] Specifically, the metal wire 106 originates from the electrode pad 103, extends along a direction substantially perpendicular to the inner wall surface 107 of the first side of the Kovar ring 101, and ultimately connects to the conductive structure 105 within the first through-hole 104 located near its second inner wall surface 108. It should be noted that this arrangement effectively shortens the extension path of the metal wire 106, thus reducing its length. Therefore, this embodiment of the application can further reduce the amount of precious metal used.

[0057] Because the metal wire 106 is routed along the shortest path (i.e., vertically), avoiding long-path routing methods such as detours and zigzags, the actual length of the metal wire 106 can be significantly shortened. The metal wire 106 is typically made of precious metals such as gold or silver to ensure good conductivity and solderability. By shortening the length of the metal wire 106, the amount of precious metals used can be directly reduced.

[0058] It should be noted that regular wiring paths facilitate template-based design and reduce manual intervention. Therefore, vertical wiring has a high degree of directional consistency and reproducibility, which is beneficial for automated processing and mass production.

[0059] Referring to FIG1, as an optional embodiment, two electrode pads 103 are provided near the first side inner wall surface 107, and the two electrode pads 103 are sequentially covered with a nickel plating layer and a gold plating layer.

[0060] It should be noted that, by providing two electrode pads 103 near the inner wall surface 107 on the first side, the current path can be better distributed, avoiding overload or hot spot problems on a single pad. Furthermore, this also helps simplify internal wiring and improve packaging efficiency.

[0061] In this embodiment, the nickel plating layer serves as the bottom layer. Due to nickel's high hardness and wear resistance, it effectively prevents damage to the solder pads during subsequent processing. Simultaneously, nickel also possesses excellent corrosion resistance, which helps extend the lifespan of the solder pads.

[0062] Gold is an excellent conductive material, and its high conductivity and oxidation resistance make it an ideal top-coating material. Therefore, the gold plating in this embodiment not only improves the electrical performance of the pads but also enhances their surface wettability, facilitating subsequent soldering processes.

[0063] The above configuration not only enhances the electrical performance and corrosion resistance of the electrode pads 103, but also improves the welding reliability of their surface. The nickel plating provides the necessary mechanical protection and corrosion resistance to the pads, while the gold plating further improves conductivity and oxidation resistance, ensuring excellent welding results. This design is particularly suitable for applications requiring high reliability and long lifespan.

[0064] Referring to FIG3, as an optional embodiment, the single-layer ceramic base 100 has four bottom electrodes 109 on the surface opposite to the Kovar ring 101; the single-layer ceramic base 100 has a rectangular structure; the four bottom electrodes 109 are respectively disposed at the four corners of the single-layer ceramic base 100.

[0065] The first bottom electrode 109 is connected to the conductive structure 105 at the end away from the metal line 106; the second bottom electrode 109 and the third bottom electrode 109 are arranged diagonally and connected by the back metal connecting line 110.

[0066] The fourth bottom electrode 109 and the electrode pad 103 away from the metal line 106 have a projected overlapping area; the single-layer ceramic base 100 has a second through hole in the projected overlapping area; the second through hole has a conductive structure 105 for connecting the fourth bottom electrode 109 and the electrode pad 103.

[0067] In this embodiment, the bottom electrodes 109 are distributed at the four corners, which helps to evenly distribute the current path, avoid local overload or hot spot problems, and improve the overall circuit stability. In addition, the layout at the four corners facilitates soldering or connection with other electronic components or circuit boards, simplifying the design of external interfaces.

[0068] Referring to FIG1, as an optional embodiment, the electrode pad 103 includes a bottom base 111 disposed on a single-layer ceramic substrate 100, and a crystal support 112 disposed on the bottom base 111; the projection of the bottom base 111 on the single-layer ceramic substrate 100 covers the crystal support 112.

[0069] It should be noted that the projection of the bottom base 111 onto the single-layer ceramic base 100 completely covers the crystal support 112, ensuring that the bottom base 111 can provide sufficient mechanical support and electrical connection path for the crystal support 112. This design in the embodiments of this application not only enhances the bonding strength between the electrode pads 103 and the single-layer ceramic base 100, but also provides a stable support structure for the crystal element.

[0070] The above configuration not only enhances the bonding strength between the electrode pads 103 and the single-layer ceramic base 100, but also provides a stable support structure for the crystal element. The large contact area of ​​the bottom base 111 increases the reliability of the electrical connection, while its projection covering the crystal support 112 provides additional mechanical protection, preventing the crystal element from being displaced or damaged due to external forces or thermal stress.

[0071] This application provides a crystal oscillator, including a quartz crystal, a package cover plate, and the aforementioned ceramic package base; the quartz crystal is connected to the electrode pads 103 through a conductive silver paste layer; the package cover plate is disposed on the surface of the Kovar ring 101 facing away from the single-layer ceramic base 100, for sealing the accommodating cavity 102.

[0072] The crystal oscillator provided in this application includes the above-mentioned ceramic packaging base, which can not only simplify the production process, improve packaging reliability and long-term stability, but also reduce the amount of precious metals used, effectively reducing production costs.

[0073] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A ceramic encapsulation base, characterized in that, The system includes a single-layer ceramic base (100) and a Kovar ring (101); the Kovar ring (101) is arranged on the surface of the single-layer ceramic base (100), and the Kovar ring (101) and the single-layer ceramic base (100) form a receiving cavity (102); an electrode pad (103) and a first through hole (104) are provided on the surface of the single-layer ceramic base (100) in the receiving cavity (102); a conductive structure (105) extending perpendicular to the single-layer ceramic base (100) is provided in the first through hole (104); a metal wire (106) is also provided on the surface of the single-layer ceramic base (100), one end of the metal wire (106) is connected to the electrode pad (103), and the other end is connected to the conductive structure (105); the width of the metal wire (106) is less than or equal to the diameter of the first through hole (104).

2. The ceramic encapsulation base according to claim 1, characterized in that, The Kovar ring (101) has a first inner wall surface (107) and a second inner wall surface (108) that are parallel to each other; the electrode pad (103) is close to the first inner wall surface (107) of the Kovar ring (101), and the first through hole (104) is close to the second inner wall surface (108) of the electrode pad (103).

3. The ceramic package base of claim 2, wherein, The metal wire (106) is arranged in a direction perpendicular to the first inner wall surface (107).

4. The ceramic encapsulation base according to claim 2, characterized in that, Two electrode pads (103) are located near the first side inner wall surface (107), and the two electrode pads (103) are sequentially covered with a nickel plating layer and a gold plating layer.

5. The ceramic package base of claim 4, wherein, The single-layer ceramic base (100) has four bottom electrodes (109) on the surface opposite to the Kovar ring (101); the single-layer ceramic base (100) has a rectangular structure; the four bottom electrodes (109) are respectively located at the four corners of the single-layer ceramic base (100).

6. The ceramic package base of claim 5, wherein, The first bottom electrode (109) is connected to the conductive structure (105) at the end opposite to the metal wire (106); the second bottom electrode (109) and the third bottom electrode (109) are arranged diagonally and connected by a back metal connecting line (110).

7. The ceramic package base of claim 6, wherein, The fourth bottom electrode (109) and the electrode pad (103) away from the metal line (106) have a projected overlap area; the single-layer ceramic base (100) is provided with a second through hole in the projected overlap area; the conductive structure (105) is provided in the second through hole for connecting the fourth bottom electrode (109) and the electrode pad (103).

8. The ceramic package base of any one of claims 1-7, wherein, The conductive structure (105) includes a conductive paste filled in the first through hole (104).

9. The ceramic encapsulation base according to any one of claims 1-7, characterized in that, The electrode pad (103) includes a bottom base (111) disposed on a single-layer ceramic substrate (100) and a crystal support (112) disposed on the bottom base (111); the projection of the bottom base (111) on the single-layer ceramic substrate (100) covers the crystal support (112).

10. A crystal oscillator, characterized in that, It includes a quartz crystal, a package cover, and a ceramic package base as described in any one of claims 1-9; the quartz crystal is connected to the electrode pad (103) through a conductive silver paste layer; the package cover is disposed on the surface of the Kovar ring (101) facing away from the single-layer ceramic base (100) for sealing the accommodating cavity (102).

Images