Ceramic shell and method for preparing ceramic shell

Abstract

This invention provides a ceramic housing and a method for manufacturing the ceramic housing. The ceramic housing includes an inner core cavity surface, an outer non-core cavity surface, and four side surfaces located between the inner core cavity surface and the outer non-core cavity surface. The ceramic housing is fabricated with a first communication structure for connecting each isolated metallized region in the inner core cavity surface to a target side surface, and a second communication structure for connecting pins on the outer non-core cavity surface to the target side surface; wherein the target side surface is at least one of the four side surfaces. By setting the first and second communication structures, the connection between pins and isolated metallized regions can be achieved through the target side surface without occupying the core area, thereby enabling the plating of the isolated metallized regions and solving the technical problem of difficulty in plating highly integrated ceramic housings in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of ceramic packaging shell technology, and particularly relates to a ceramic shell and a method for preparing the ceramic shell. Background Technology

[0002] As system integration increases, the number of chips and components inside the package increases, and the layout density inside the package also increases. Since the chips in multi-chip ceramic package need to be interconnected but not interconnected with external pins, there will be many isolated areas inside the package that are not connected to external pins.

[0003] Generally, ceramic shells with isolated metallized areas in the core area of ​​a core with a lead frame are designed to achieve plating using either wire bonding or laser breaking. However, the wire bonding method requires pre-reserving bonding areas in the core area, and the laser breaking method also requires pre-reserving breaking areas in the core area. Both methods leave excess material in the core area. When the core area layout density is high or the requirements for excess material inside the cavity are strict, plating cannot be performed. Summary of the Invention

[0004] In view of this, the present invention provides a ceramic shell and a method for preparing the ceramic shell, aiming to solve the problem that plating cannot be performed when the core area layout density is large or the requirements for excess material inside the cavity are strict.

[0005] A first aspect of the present invention provides a ceramic shell, the ceramic shell including an inner core cavity surface, an outer non-core cavity surface, and four side surfaces located between the inner core cavity surface and the outer non-core cavity surface;

[0006] The ceramic housing is fabricated with a first communication structure for connecting each isolated metallized region in the inner core cavity surface to the target side surface, and a second communication structure for connecting the pins on the outer non-core cavity surface to the target side surface; wherein the target side surface is at least one of the four sides.

[0007] A second aspect of this invention provides a method for preparing a ceramic shell, used to prepare the ceramic shell as described in the first aspect above; the method includes:

[0008] A first communication structure is fabricated to connect each isolated metallized region in the inner cavity surface to the target side surface, and a second communication structure is fabricated to connect the pins on the outer non-cavity surface to the target side surface.

[0009] Metallization patterns are printed on the target side, so that each isolated metallized area on the inner core cavity surface of the ceramic housing is connected to the pin on the outer non-core cavity surface.

[0010] Each isolated metallized area is plated, and the metallized pattern on the target side is removed after the plating is completed.

[0011] The ceramic shell and its fabrication method provided in this invention include an inner core cavity surface, an outer non-core cavity surface, and four side surfaces between the inner core cavity surface and the outer non-core cavity surface. The ceramic shell is fabricated with a first communication structure for connecting each isolated metallized region in the inner core cavity surface to a target side surface, and a second communication structure for connecting pins on the outer non-core cavity surface to the target side surface; wherein the target side surface is at least one of the four side surfaces. By setting the first and second communication structures, the connection between pins and isolated metallized regions can be achieved via the target side surface without occupying the core area, thereby enabling plating of the isolated metallized regions and solving the technical problem of difficulty in plating highly integrated ceramic shells in the prior art. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the external structure of the ceramic shell provided in an embodiment of the present invention;

[0014] Figure 2 This is a schematic diagram of the internal structure of the ceramic shell provided in an embodiment of the present invention;

[0015] Figure 3 This is a schematic diagram of the cross-sectional structure of the ceramic shell provided in an embodiment of the present invention;

[0016] Figure 4 This is a flowchart illustrating the implementation of the method for preparing the ceramic shell provided in this embodiment of the invention;

[0017] Figure 5 This is a plating process diagram provided in an embodiment of the present invention;

[0018] Figure 6 This is a plating process diagram provided in another embodiment of the present invention;

[0019] Figure 7 This is a top view of the ceramic housing with lead frame provided in an embodiment of the present invention;

[0020] Figure 8 This is a top view of the ceramic housing with part of the lead frame removed, provided in an embodiment of the present invention. Detailed Implementation

[0021] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0022] Multi-chip ceramic package (MCC) is a typical example of high-reliability, high-density integrated circuits. MCCs can encapsulate two or more chips with different functions, such as passive devices and MEMS. Chips can be arranged in 2D or stacked in three dimensions, reducing package size and achieving device miniaturization. Besides protecting and scaling up the multiple bare chips within the package, the ceramic package also provides electrical interconnection between the internal packaged chips and various components. This allows multiple packages to be integrated into one, significantly reducing package size and weight while decreasing the total number of solder points, shortening component connection paths, and improving electrical performance.

[0023] Due to the high-density integration of multi-chip ceramic housings, the core area typically contains multiple isolated metallized regions. Furthermore, due to the high density of the core area layout, it is difficult to plate these isolated metallized regions using traditional methods. This invention provides a ceramic housing that, by setting two interconnecting structures, enables the connection between pins and isolated metallized regions without occupying the core area, thereby allowing for the plating of these isolated metallized regions.

[0024] Figure 1 This is a schematic diagram of the structure of the ceramic shell provided in an embodiment of the present invention. Figure 1 As shown, the ceramic shell has an inner core cavity surface 11, an outer non-core cavity surface 12, and four side surfaces 13 located between the inner core cavity surface and the outer non-core cavity surface.

[0025] In this embodiment of the invention, the inner core cavity surface 11 includes multiple core regions (such as... Figure 1 The inner core cavity surface 11 (excluding the edge portion) and the non-core area (e.g., the non-shaded portion in the inner core cavity surface 11) are provided with a plurality of pins (e.g., ...). In the non-core area, there are some regions that are difficult to connect to the pins, which are called isolated metallized regions. Figure 1 The ceramic shell structure shown is merely an example of the present invention and is not intended to be limiting.

[0026] Figure 2 This is a schematic diagram of the internal structure of the ceramic shell provided in an embodiment of the present invention. Figure 2As shown, in some embodiments, the ceramic housing is provided with a first communication structure 14 for connecting each isolated metallized region in the inner core cavity surface 11 to the target side, and a second communication structure 15 for connecting the pins on the outer non-core cavity surface 12 to the target side; wherein the target side is at least one of the four sides 13.

[0027] In this embodiment of the invention, each isolated metallized region can be connected to a nearby side, which is then designated as the target side. The pin connected to the target side can be any pin, but to save costs and minimize the impact on the ceramic casing, a pin as close to the target side as possible should be selected.

[0028] In this embodiment of the invention, by setting the first connecting structure 14 and the second connecting structure 15, the pins can be connected to the isolated metallized area via the target side without occupying the core area, thereby plating the isolated metallized area and solving the technical problem that it is difficult to achieve plating on highly integrated ceramic shells in the prior art.

[0029] In some embodiments, the first interconnect structure 14 includes a plurality of first interconnect holes and a plurality of first wires.

[0030] Each isolated metallized region is connected to the upper end of a corresponding first interconnect hole; the lower end of each first interconnect hole is connected to one end of a corresponding first conductor; and the other end of each first conductor is connected to the side of the target.

[0031] In some embodiments, the second interconnection structure includes a second interconnection hole and a second wire;

[0032] The pins on the outer non-core cavity surface are connected to the lower end of the second interconnect hole; the upper end of the second interconnect hole is connected to one end of the second wire; and the other end of the second wire is connected to the target side.

[0033] In this embodiment of the invention, the first interconnecting hole, the first conductive wire, the second interconnecting hole, and the second conductive wire are all set during the ceramic shell fabrication process. After the ceramic shell is fabricated, metal is printed on the target side to achieve the connection between the isolated metal area and the pin. For example, during the shell wiring design, the isolated metallized area inside the core cavity can be punched and internally routed to the edge of the shell without leads, i.e., the short side of the shell, while the pin ① is also internally connected to the short side of the shell.

[0034] In this embodiment of the invention, there may be one or four second interconnecting holes, depending on the manufacturing cost and plating requirements, and no limitation is made here. The number of second conductive lines is between one and four, depending on the number of target sides, and no limitation is made here. Each second interconnecting hole is connected to at least one second conductive line.

[0035] Figure 3 This is a schematic cross-sectional view of the ceramic shell provided in an embodiment of the present invention. Figure 3 As shown, in some embodiments, the ceramic housing further includes a sealing ring 16. The four sides include two short sides and two long sides; the sealing ring 16 is disposed on the inner core cavity surface and close to one of the long sides.

[0036] In some embodiments, the ceramic shell may be composed of a ceramic body, a sealing ring, a lead wire, and an insulating ceramic strip. The ceramic material is 90% alumina and may be manufactured using a multi-layer alumina tungsten metallization high-temperature co-firing process. The sealing ring material may be an iron-nickel-cobalt alloy, the lead wire may be an iron-nickel alloy, and the ceramic body may be welded to the sealing ring, the lead wire, and the insulating ceramic strip using silver-copper solder.

[0037] Figure 4 This is a flowchart illustrating the implementation of the method for preparing the ceramic shell provided in this embodiment of the invention. Figure 4 As shown, in some embodiments, the method for preparing the ceramic shell is used to prepare the ceramic shell as shown in any of the above embodiments. The method includes:

[0038] S401, a first communication structure 14 is prepared to connect each isolated metallized region in the inner core cavity surface with the target side surface, and a second communication structure 15 is prepared to connect the pins on the outer non-core cavity surface with the target side surface.

[0039] In this embodiment of the invention, S401 is the preparation process of the main body of the ceramic shell. After the main body is prepared, it is plated to complete the preparation of the ceramic shell. The plating process is shown in S402 and S403.

[0040] S402, prints a metallized pattern on the target side, so that each isolated metallized area on the inner core surface of the ceramic housing is connected to the pin on the outer non-core surface.

[0041] In this embodiment of the invention, the purpose of printing the metallized pattern on the target side is to connect the first connected structure 14 and the second connected structure 15 on the target side, thereby realizing the connection between the pin and the isolated metallized area. Therefore, for the side that did not prepare the above two connected structures in step S401, the metallized pattern can be omitted.

[0042] S403, plate each isolated metallized area, and remove the metallized pattern on the target side after the plating is completed.

[0043] In this embodiment of the invention, the plating method can be electroplating or chemical plating, and is not limited thereto. After the plating is completed, the connection between the pin and the isolated metallized area needs to be disconnected. Therefore, the metallized pattern on the target side needs to be removed. The removal method can be polishing, etching, etc., and is not limited thereto.

[0044] Figure 5 This is a plating process flowchart provided in an embodiment of the present invention. Figure 5 As shown, in some embodiments, S403 may include:

[0045] S501, nickel is electroplated onto each isolated metallized area.

[0046] In this embodiment of the invention, nickel plating requires that all areas inside the casing be connected to the cathode of the plating solution. The prerequisite for nickel plating is that all four sides are target sides. During casing design, the pin pads can be connected inside the casing to the sides. Then, during the fabrication of the green ceramic part, the four sides of the casing are printed with full-surface metallization patterns, thus achieving connectivity between all metallized areas of the casing and the four sides.

[0047] S502, grind and polish the two long sides to remove the metallized patterns on the two long sides.

[0048] In this embodiment of the invention, the metallization pattern printing on the four sides is for nickel electroplating, but the four sides are not needed for gold electroplating. Therefore, the metallization patterns on the two longer sides can be removed. When all four sides are target sides, in order to still perform gold electroplating after removing the metallization patterns on the two longer sides, the two connected structures should preferably connect the shorter sides.

[0049] S503 involves electroplating gold into each isolated metallized area after nickel plating.

[0050] S504, grind and polish the two short sides to remove the metallized patterns on the two short sides.

[0051] In some embodiments, S501 may include:

[0052] The sides of each target are connected by metal wire;

[0053] The metal wire is connected to the cathode of the electroplating solution, and nickel is electroplated onto each isolated metallized area.

[0054] In this embodiment of the invention, during electroplating, metal wires can be used to bind the ceramic parts together to connect them to the cathode of the electroplating solution, so that all areas of the outer shell are electrically connected, thereby achieving nickel electroplating.

[0055] Figure 6 This is a plating process diagram provided in another embodiment of the present invention. (See diagram below.) Figure 6 As shown, in some embodiments, S401 may include:

[0056] S601, chemical nickel plating is performed on each isolated metallized area;

[0057] S602 involves electroplating gold onto isolated metallized areas after electroless nickel plating.

[0058] S603, the two short sides are ground and polished to remove the metallized patterns on the two short sides.

[0059] In this embodiment, electroless nickel plating can be used only when the short side is the target side. Since the welding strength of the ceramic body brazing lead frame after electroless nickel plating is lower than that after electroplating nickel, electroplating nickel is generally used to plate the ceramic parts in applications with high reliability requirements.

[0060] Figure 7 This is a top view of the ceramic housing with lead frame provided in an embodiment of the present invention. Figure 8 This is a top view of the ceramic housing with part of the lead frame removed, as provided in an embodiment of the present invention. Figure 7 and 8 As shown, in some embodiments, S503 or S602 may include:

[0061] The metallization on both sides of the housing pin pads is ground, and then the lead frame 17 is brazed to connect all areas of the housing with the lead frame. During gold plating, the lead frame 17 is connected to the cathode of the electroplating solution to make all areas of the housing conductive and thus achieve gold plating. After plating is completed, the short side of the lead frame 17 is cut off, and the metallization on the short side is ground to disconnect the isolated metallized area from the pin.

[0062] In some embodiments, after the green ceramic part of the housing is thermally cut into individual pieces, a metallization pattern can be printed on the target side to connect the isolated metallized area with the pin ①, and then the green ceramic part can be sintered.

[0063] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0064] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0065] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0066] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0067] In the embodiments provided by this invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0068] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0069] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0070] If an integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for preparing a ceramic shell, characterized in that, The method is used to fabricate a ceramic housing; the ceramic housing includes an inner core cavity surface, an outer non-core cavity surface, and four side surfaces located between the inner core cavity surface and the outer non-core cavity surface; the ceramic housing is fabricated with a first communication structure for connecting each isolated metallized region in the inner core cavity surface to a target side surface, and a second communication structure for connecting a pin on the outer non-core cavity surface to the target side surface; wherein, the target side surface is at least one of the four side surfaces; the isolated metallized region is an isolated region inside the ceramic housing that is not connected to the pin and is used to realize interconnection of multiple chips; the first communication structure and the second communication structure are used to realize a temporary electrical connection between the isolated metallized region and the pin through the target side surface during the plating process, and the temporary electrical connection is disconnected by removing the metallized pattern of the target side surface after plating is completed; The method includes: preparing a first communication structure for connecting each isolated metallized region in the inner core cavity surface to a target side surface, and a second communication structure for connecting pins on the outer non-core cavity surface to the target side surface; printing a metallized pattern on the target side surface, such that each isolated metallized region in the inner core cavity surface of the ceramic housing is connected to a pin on the outer non-core cavity surface; plating each isolated metallized region, and removing the metallized pattern on the target side surface after plating; the four sides include two short sides and two long sides; The process of plating each isolated metallized area and removing the metallized pattern on the target side after plating includes: electroplating nickel on each isolated metallized area; all four sides are target sides; polishing the two long sides to remove the metallized pattern on the two long sides; electroplating gold on each isolated metallized area after nickel plating; and polishing the two short sides to remove the metallized pattern on the two short sides. The process of electroplating nickel into each isolated metallized region includes: connecting each target side with a metal wire; connecting the metal wire to the cathode of the electroplating solution; and electroplating nickel into each isolated metallized region. The process of electroplating gold on each isolated metallized region includes: welding a lead frame and a sealing ring to the pins on the outer non-core cavity surface; connecting the lead frame to the cathode of the electroplating solution to electroplat gold on each isolated metallized region; and removing the lead frames on both sides of the two short sides.

2. A method for preparing a ceramic shell, characterized in that, The method is used to fabricate a ceramic housing; the ceramic housing includes an inner core cavity surface, an outer non-core cavity surface, and four side surfaces located between the inner core cavity surface and the outer non-core cavity surface; the ceramic housing is fabricated with a first communication structure for connecting each isolated metallized region in the inner core cavity surface to a target side surface, and a second communication structure for connecting a pin on the outer non-core cavity surface to the target side surface; wherein, the target side surface is at least one of the four side surfaces; the isolated metallized region is an isolated region inside the ceramic housing that is not connected to the pin and is used to realize interconnection of multiple chips; the first communication structure and the second communication structure are used to realize a temporary electrical connection between the isolated metallized region and the pin through the target side surface during the plating process, and the temporary electrical connection is disconnected by removing the metallized pattern of the target side surface after plating is completed; The method includes: preparing a first communication structure for connecting each isolated metallized region in the inner core cavity surface to a target side surface, and a second communication structure for connecting pins on the outer non-core cavity surface to the target side surface; printing a metallized pattern on the target side surface, such that each isolated metallized region in the inner core cavity surface of the ceramic housing is connected to a pin on the outer non-core cavity surface; plating each isolated metallized region, and removing the metallized pattern on the target side surface after plating; the four sides include two short sides and two long sides; The process of plating each isolated metallized area and removing the metallized pattern on the target side after plating includes: electroless nickel plating on each isolated metallized area; electroplating gold on each isolated metallized area after electroless nickel plating; targeting only the two short sides; and polishing the two short sides to remove the metallized pattern on the two short sides. The process of electroplating gold on each isolated metallized region includes: welding a lead frame and a sealing ring to the pins on the outer non-core cavity surface; connecting the lead frame to the cathode of the electroplating solution to electroplat gold on each isolated metallized region; and removing the lead frames on both sides of the two short sides.

3. The method for preparing the ceramic shell according to claim 1 or 2, characterized in that, After printing the metallized pattern on the target side, the method further includes: The ceramic shell is sintered into a ceramic part.

4. A ceramic shell, characterized in that, The ceramic shell is prepared by the method according to any one of claims 1-3; the ceramic shell includes an inner core cavity surface, an outer non-core cavity surface, and four side surfaces located between the inner core cavity surface and the outer non-core cavity surface; The ceramic housing is provided with a first communication structure for connecting each isolated metallized region in the inner core cavity surface to the target side surface, and a second communication structure for connecting the pins on the outer non-core cavity surface to the target side surface; wherein the target side surface is at least one of the four sides. The isolated metallized region is an isolated area inside the ceramic housing that is not connected to the pin and is used to interconnect multiple chips. The first and second connecting structures are used to achieve a temporary electrical connection between the isolated metallized area and the pin via the target side during the plating process, and the temporary electrical connection is disconnected by removing the metallized pattern on the target side after plating is completed.

5. The ceramic shell according to claim 4, characterized in that, The first interconnection structure includes a plurality of first interconnect holes and a plurality of first wires; Each isolated metallized region is connected to the upper end of a corresponding first interconnect hole; the lower end of each first interconnect hole is connected to one end of a corresponding first conductor; and the other end of each first conductor is connected to the target side.

6. The ceramic shell according to claim 4, characterized in that, The second interconnection structure includes a second interconnection hole and a second wire; The pins on the outer non-core cavity surface are connected to the lower end of the second interconnect hole; the upper end of the second interconnect hole is connected to one end of the second wire; and the other end of the second wire is connected to the target side.

7. The ceramic shell according to claim 4, characterized in that, The ceramic shell further includes a sealing ring; the four sides include two short sides and two long sides; the sealing ring is disposed on the inner core cavity surface and close to one of the long sides.

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