阅读说明：本技术 射频SiP陶瓷封装外壳及其制作方法 (Radio frequency SiP ceramic packaging shell and manufacturing method thereof ) 是由 刘俊永 吴建利 王伟 于 2020-12-07 设计创作，主要内容包括：本发明公开了一种射频SiP陶瓷封装外壳及其制作方法,其包括多层布线陶瓷基板、金属围框和金属盖板,所述金属围框焊接于所述多层布线陶瓷基板的表面,所述金属盖板与所述金属围框焊接固定从而将所述技术围框封盖；所述多层布线陶瓷基板设有带地共面波导-类同轴-带线-类同轴-带地共面波导的2级阶梯形式阻抗匹配传输线结构,在保证封装外壳气密性的同时,可明显降低射频信号传输插损,实现封装外壳的轻量化和小型化。(The invention discloses a radio frequency SiP ceramic packaging shell and a manufacturing method thereof, wherein the radio frequency SiP ceramic packaging shell comprises a multilayer wiring ceramic substrate, a metal enclosing frame and a metal cover plate, wherein the metal enclosing frame is welded on the surface of the multilayer wiring ceramic substrate, and the metal cover plate and the metal enclosing frame are welded and fixed so as to seal the technical enclosing frame; the multilayer wiring ceramic substrate is provided with a 2-stage ladder-type impedance matching transmission line structure with the ground coplanar waveguide, similar coaxial line and similar ground coplanar waveguide, so that the air tightness of the packaging shell is ensured, the transmission insertion loss of radio frequency signals can be obviously reduced, and the light weight and the miniaturization of the packaging shell are realized.)

1. The radio frequency SiP ceramic packaging shell is characterized by comprising a multilayer wiring ceramic substrate, a metal enclosure frame and a metal cover plate, wherein the metal enclosure frame is welded on the surface of the multilayer wiring ceramic substrate, and the metal cover plate and the metal enclosure frame are welded and fixed so as to cover the metal enclosure frame;

wherein the multilayer wiring ceramic substrate includes:

a multilayer ceramic substrate having opposing first and second surfaces;

the transmission line structure comprises grounded coplanar waveguide transmission lines respectively arranged on the first surface and the second surface and a strip line transmission line arranged in the multilayer ceramic substrate, wherein two ends of the strip line transmission line are respectively connected with the grounded coplanar waveguide transmission lines arranged on the first surface and the second surface through two similar coaxial transmission lines with matched impedance to form a 2-stage trapezoidal impedance matching transmission line structure of the grounded coplanar waveguide-similar coaxial-strip line-similar coaxial-grounded coplanar waveguide, and the similar coaxial transmission line is arranged in the multilayer ceramic substrate;

and the electric grounding pattern comprises a first electric grounding pattern arranged in the multilayer ceramic substrate, a second electric grounding pattern arranged on the first surface and a third electric grounding pattern arranged on the second surface, the first electric grounding pattern is respectively and electrically connected with the second electric grounding pattern and the third electric grounding pattern through holes, and the through holes are arranged in the multilayer ceramic substrate.

2. The radio frequency SiP ceramic package of claim 1, wherein the metal frame is selected from a 4J29 alloy or a 4J42 alloy.

3. The radio frequency SiP ceramic package of claim 1, wherein the surface of the metal enclosure is plated with a nickel layer and a gold layer in sequence from inside to outside.

4. The radio frequency SiP ceramic package of claim 1, wherein the metal lid is made of a material selected from the group consisting of 4J29 alloy and 4J42 alloy.

5. The radio frequency SiP ceramic package of claim 4, wherein the surface of the metal lid is plated with a nickel layer and a gold layer in sequence from inside to outside.

6. The radio frequency SiP ceramic package of claim 1, wherein the multilayer ceramic substrate is selected from one of an alumina ceramic substrate, an aluminum nitride ceramic substrate, an LTCC ceramic substrate.

7. The radio frequency SiP ceramic package of claim 1, wherein the quasi-coaxial transmission lines comprise at least 2, and each 2 quasi-coaxial transmission lines are interconnected by the strip line transmission line.

8. The radio frequency SiP ceramic package of claim 1, wherein the first electrical ground pattern comprises at least two layers, and each layer of the first electrical ground pattern is electrically connected to the second electrical ground pattern and the third electrical ground pattern through the via, respectively.

9. A method of making a radio frequency SiP ceramic package according to any of claims 1-8, comprising the steps of:

according to the design, punching through holes on the green ceramic chips of the corresponding layers, filling the through holes with conductor slurry, screen-printing circuit patterns comprising coplanar waveguide transmission lines on the surfaces of the green ceramic chips of the first surface and the second surface of the corresponding multilayer ceramic substrate, and simultaneously screen-printing circuit patterns comprising strip line transmission lines and electrical connection patterns on the green ceramic chips of the corresponding layers;

laminating the multilayer ceramic chips printed with the patterns according to a design sequence to form a substrate green body, sintering, forming a 2-level step-shaped three-dimensional transmission line structure with the ground coplanar waveguide-similar coaxial-strip line-similar coaxial-ground coplanar waveguide by the radio frequency signal input/output interface circuit patterns in the substrate and on the surface of the substrate, and preparing the multilayer wiring ceramic substrate containing the radio frequency signal input/output interface circuit patterns and the electric grounding patterns;

the metal enclosure frame and the multilayer wiring ceramic substrate are brazed together through solder to form a hermetic sealing cavity;

and after the assembly of various active devices on the multilayer wiring ceramic substrate is completed, the metal enclosure frame is sealed and covered by the metal cover plate through parallel seal welding or tin soldering to manufacture the radio frequency SiP ceramic packaging shell.

10. The method of claim 9, wherein the solder is selected from the group consisting of silver-copper alloy, gold-germanium alloy, gold-tin alloy, lead-tin alloy, and tin-silver-copper alloy.

Technical Field

The invention belongs to the technical field of integrated circuit packaging, and particularly relates to a radio frequency SiP ceramic packaging shell and a manufacturing method thereof.

Background

A radio frequency SiP (System in a Package) is a device that combines a plurality of radio frequency chips with different functions and passive devices into a standard Package to implement a certain System or subsystem function. The radio frequency SiP Ceramic package mostly uses an HTCC (High Temperature Cofired Ceramic) multilayer wiring substrate or an LTCC (Low Temperature Cofired Ceramic) multilayer wiring substrate as a carrier of a radio frequency device and a circuit, and integrates one or more radio frequency input/output interface circuit patterns in the Ceramic substrate.

The QFN type radio frequency SiP ceramic package shell integrates radio frequency input/output interfaces at the periphery of the bottom of the ceramic substrate, has small volume, is suitable for SMT process, and is increasingly used for radio frequency SiP package.

The existing RF input/output interface circuit pattern design of the QFN type RF SiP ceramic packaging shell usually adopts a 1-stage ladder-type transmission line structure of coplanar waveguide-type coaxial-coplanar waveguide. Because the structure comprises the through holes vertically penetrating through the upper surface and the lower surface of the substrate, the air leakage phenomenon of the shell at the substrate is easily caused, and the sealing performance is reduced. Therefore, it is necessary to additionally solder a corresponding metal foil on the rf i/o interface pattern at the bottom of the substrate to "block" the leakage path and improve the sealing performance of the package. However, impedance mismatching of the rf transmission line structure is easily caused, which increases the transmission loss of the rf signal, increases the number of manufacturing steps, increases the weight of the package, and is not favorable for light weight and miniaturization of the rf SiP.

Disclosure of Invention

In view of the above, the present invention is directed to a radio frequency SiP ceramic package, which eliminates a via hole penetrating vertically through the upper and lower surfaces of a multilayer ceramic substrate by designing an impedance matching transmission line structure in the form of a "2-step" of a "band-to-ground coplanar waveguide-like coaxial-band-line-like coaxial-band-to-band coplanar waveguide" on the surface and inside the multilayer ceramic substrate, and reduces the signal transmission loss of the radio frequency input/output interface circuit of the obtained multilayer wired ceramic substrate.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention firstly provides a radio frequency SiP ceramic packaging shell which comprises a multilayer wiring ceramic substrate, a metal enclosing frame and a metal cover plate, wherein the metal enclosing frame is welded on the surface of the multilayer wiring ceramic substrate, and the metal cover plate and the metal enclosing frame are welded and fixed so as to seal the technical enclosing frame;

wherein the multilayer wiring ceramic substrate includes:

a multilayer ceramic substrate having opposing first and second surfaces;

the transmission line structure comprises grounded coplanar waveguide transmission lines respectively arranged on the first surface and the second surface and a strip line transmission line arranged in the multilayer ceramic substrate, wherein two ends of the strip line transmission line are respectively connected with the grounded coplanar waveguide transmission lines arranged on the first surface and the second surface through two similar coaxial transmission lines with matched impedance to form a 2-stage trapezoidal impedance matching transmission line structure of the grounded coplanar waveguide-similar coaxial-strip line-similar coaxial-grounded coplanar waveguide, and the similar coaxial transmission line is arranged in the multilayer ceramic substrate;

and the electric grounding pattern comprises a first electric grounding pattern arranged in the multilayer ceramic substrate, a second electric grounding pattern arranged on the first surface and a third electric grounding pattern arranged on the second surface, the first electric grounding pattern is respectively and electrically connected with the second electric grounding pattern and the third electric grounding pattern through holes, and the through holes are arranged in the multilayer ceramic substrate.

Furthermore, the material of the metal enclosure frame is selected from 4J29 alloy or 4J42 alloy.

Furthermore, a nickel layer and a gold layer are sequentially plated on the surface of the metal enclosure frame from inside to outside.

Furthermore, the material of the metal cover plate is selected from 4J29 alloy or 4J42 alloy.

Preferably, the surface of the metal cover plate is plated with a nickel layer and a gold layer in sequence from inside to outside.

Further, the multilayer ceramic substrate is selected from one of an alumina ceramic substrate, an aluminum nitride ceramic substrate and an LTCC ceramic substrate.

Further, the number of the quasi-coaxial transmission lines is at least 2, and every 2 quasi-coaxial transmission lines are interconnected through the strip line transmission line.

Further, the first electrical grounding pattern comprises at least two layers, and each layer of the first electrical grounding pattern is electrically connected with the second electrical grounding pattern and the third electrical grounding pattern respectively through the through holes.

The invention also provides a manufacturing method of the radio frequency SiP ceramic package shell, which comprises the following steps:

according to the design, punching through holes on the green ceramic chips of the corresponding layers, filling the through holes with conductor slurry, screen-printing circuit patterns comprising coplanar waveguide transmission lines on the surfaces of the green ceramic chips of the first surface and the second surface of the corresponding multilayer ceramic substrate, and simultaneously screen-printing circuit patterns comprising strip line transmission lines and electrical connection patterns on the green ceramic chips of the corresponding layers;

laminating the multilayer ceramic chips printed with the patterns according to a design sequence to form a substrate green body, sintering, forming a 2-level step-shaped three-dimensional transmission line structure with the ground coplanar waveguide-similar coaxial-strip line-similar coaxial-ground coplanar waveguide by the radio frequency signal input/output interface circuit patterns in the substrate and on the surface of the substrate, and preparing the multilayer wiring ceramic substrate containing the radio frequency signal input/output interface circuit patterns and the electric grounding patterns;

the metal enclosure frame and the multilayer wiring ceramic substrate are brazed together through solder to form a hermetic sealing cavity;

and after the assembly of various active devices on the multilayer wiring ceramic substrate is completed, the metal enclosure frame is sealed and covered by the metal cover plate through parallel seal welding or tin soldering to manufacture the radio frequency SiP ceramic packaging shell.

Further, the solder is selected from silver-copper alloy, gold-germanium alloy, gold-tin alloy, lead-tin alloy or tin-silver-copper alloy.

Compared with the prior art, the invention has the following beneficial effects:

the radio frequency SiP ceramic packaging shell improves a multilayer wiring ceramic substrate, the multilayer wiring ceramic substrate is additionally provided with at least two layers of electric grounding patterns and at least one layer of strip line transmission lines inside the multilayer ceramic substrate, and two ends of each strip line transmission line are respectively connected with the grounded coplanar waveguide transmission lines on the upper surface and the lower surface of the multilayer ceramic substrate through two similar coaxial transmission lines with impedance matching, so that a 2-level ladder-type impedance matching transmission line structure of grounded coplanar waveguide-similar coaxial-strip line-similar coaxial-grounded coplanar waveguide is formed, and the transmission loss of a radio frequency input/output interface circuit can be reduced.

When the radio frequency SiP ceramic packaging shell is prepared by the multilayer wiring ceramic substrate, the packaging shell can be sealed without welding a metal sheet at the bottom of the multilayer wiring ceramic substrate, so that the air tightness of the packaging shell is improved, the manufacturing process steps of the radio frequency SiP ceramic packaging shell can be simplified, the weight of the packaging shell is reduced, and the size of the packaging shell is reduced.

Because the novel 2-level ladder-type transmission line structure of the 'strip-ground coplanar waveguide-similar coaxial-strip line-similar coaxial-strip-ground coplanar waveguide' is used in the multilayer wiring ceramic substrate, through holes vertically penetrating through the upper surface and the lower surface of the multilayer ceramic substrate are eliminated, the risk of gas leakage of the substrate is greatly reduced, the sealing reliability of the radio frequency SiP ceramic packaging shell is improved, and the measured gas leakage rate R1 of the packaging shell is less than or equal to 1 multiplied by 10^-9Pa·m³/s。

Drawings

FIG. 1 is a three-dimensional structural view of a multilayer wiring ceramic substrate including a "2-step ladder" type transmission line structure of "band-to-ground coplanar waveguide-like coaxial-band line-like coaxial-to-band coplanar waveguide" in a preferred embodiment of the present invention;

fig. 2 is a schematic cross-sectional structure diagram of a radio frequency SiP ceramic package in embodiment 1 of the present invention;

fig. 3 is a schematic cross-sectional structure diagram of a radio frequency SiP ceramic package according to embodiment 2 of the present invention;

fig. 4 is a schematic cross-sectional view of the rf SiP ceramic package in comparative example 1.

In the figure: coplanar waveguide transmission line 10, electrical connection pattern 20, solder 30, metal enclosure frame 40, metal cover plate 50, strip line transmission line 60, coaxial-like transmission line 70, multilayer ceramic substrate 80, metal sheet 90.

Detailed Description

In order that the invention may be more fully understood, reference will now be made to the specific embodiments illustrated. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In a first aspect of the present invention, a radio frequency SiP ceramic package housing is disclosed, which comprises a multilayer wired ceramic substrate, a metal enclosure frame 40 and a metal cover plate 50, specifically, as shown in fig. 2-3, the metal enclosure frame 40 is welded to the surface of the multilayer wired ceramic substrate, so as to form a cavity with the multilayer wired ceramic substrate, the welding is performed by a welding method conventional in the art, that is, by a solder 30, and the welding is performed between the metal enclosure frame 40 and the multilayer wired ceramic substrate by the solder 30, the type of the solder 30 is not particularly limited, and the solder is matched according to the material of the metal enclosure frame 40, and may be selected from a silver copper alloy, a gold germanium alloy, a gold tin alloy, a lead tin alloy or a tin-silver copper alloy. The metal cover plate 50 is sealed on the metal surrounding frame 40, so that the metal cover plate 50, the metal surrounding frame 40 and the multilayer wiring ceramic substrate form a sealed package housing, the sealing manner of the metal cover plate 50 and the metal surrounding frame 40 is not particularly limited, and any manner commonly used in the field of package housings, such as parallel sealing or soldering, is not specifically described herein. It should be noted that the number of the metal cover plates 50 is the same as that of the metal enclosure frame 40, and the number of the metal enclosure frames 40 may be one or more, and is adjusted according to the need of the package housing, and therefore, there is no particular limitation here.

Further, the material of the metal surrounding frame 40 and the metal cover plate 50 is not particularly limited, and any material conventionally used in the art for package housings may be used, and specific examples include, but are not limited to, 4J29 alloy or 4J42 alloy, and the surfaces of the metal surrounding frame 40 and the metal cover plate 50 are plated with nickel layer and gold layer from inside to outside.

Further, referring to fig. 1 to 3, the multilayer wiring ceramic substrate includes a multilayer ceramic substrate 80, a transmission line structure composed of a coplanar waveguide transmission line 10, a quasi-coaxial transmission line 70 and a strip line transmission line 60, and an electrical ground pattern 20 is further provided inside and on a surface of the multilayer ceramic substrate 80.

Specifically, the multilayer ceramic substrate 80 is a plate-shaped structure having a first surface and a second surface opposite to each other, which is a substrate structure conventional in the art, and is generally formed by sequentially laminating a plurality of green ceramic sheets and sintering the laminated green ceramic sheets, and will not be described in detail herein since it is a known technology. The material of the multilayer ceramic substrate 80 is not particularly limited, and any ceramic substrate conventionally used in the art may be used in the present invention, and specific examples include but are not limited to one of an alumina ceramic substrate, an aluminum nitride ceramic substrate, and an LTCC ceramic substrate, which can be adjusted as needed by those skilled in the art, and thus, is not particularly limited herein.

Further, a transmission line structure is provided on the surface and inside of the multilayer ceramic substrate 80, thereby forming an interconnection channel. Specifically, the coplanar waveguide transmission line 10 is respectively disposed on the first surface and the second surface of the multilayer ceramic substrate 80, and one or more rf signal input/output interface circuit patterns are formed by the coplanar waveguide transmission line 10, so that the circuit patterns are designed on the first surface and the second surface of the multilayer ceramic substrate 80 according to the requirement, and therefore, the coplanar waveguide transmission line 10 is not specifically described herein. The strip line transmission line 60 and the quasi-coaxial transmission line 70 are disposed inside the multilayer ceramic substrate 80, and specifically, the quasi-coaxial transmission line 70 has at least two lines, which are respectively connected to the coplanar waveguide transmission lines 10 on the surface of the multilayer ceramic substrate 80, and the quasi-coaxial transmission lines 70 are respectively connected to both ends of the strip line transmission line 60, and the impedances of the quasi-coaxial transmission lines 70 connected to both ends of the strip line transmission line 60 are matched, so that the strip line transmission line 60 is connected to the coplanar waveguide transmission lines 10, thereby forming a 2-step impedance-matched transmission line structure of the coplanar waveguide transmission line on the first surface, the quasi-coaxial transmission line, the strip line transmission line, the quasi-coaxial transmission line, and the coplanar waveguide transmission line on the second surface, which can reduce the transmission loss of the rf signal input/output interface circuit. And since the through-holes vertically penetrating the upper and lower surfaces of the substrate are eliminated, the airtightness of the multilayer ceramic substrate 80 can be greatly improved. And it is not necessary to attach a metal foil to the second surface of the multilayer ceramic substrate 80.

Further, the electrical connection patterns 20 are respectively provided on the inner and surface of the multilayer ceramic substrate 80, and the surface and inner are connected by a via hole provided in the inner portion of the multilayer ceramic substrate 80, as shown in fig. 2 to 3.

Further, the coaxial-like transmission lines 70 include at least 2, and each 2 coaxial-like transmission lines 70 are interconnected through the strip line transmission line 60.

Further, the electrical connection pattern located inside the multilayer ceramic substrate 80 has at least two layers, and both communicate with the electrical connection pattern 20 of the surface through the through-hole.

The second aspect of the invention discloses a manufacturing method of the radio frequency SiP ceramic package housing of the first aspect of the invention, comprising the following steps:

according to the design, through holes are punched on the green ceramic chips of the corresponding layers, and the through holes are filled with conductor slurry. Screen printing a circuit pattern including the coplanar waveguide transmission line 10 on the surface of the green tile corresponding to the first and second surfaces of the multilayer ceramic substrate 80, and screen printing a circuit pattern including the stripline transmission line 60 and the electrical connection pattern 20 on the green tile corresponding to the layer;

the multilayer ceramic chip printed with the patterns is laminated into a substrate green body according to the design sequence, and after sintering, the radio frequency signal input/output interface circuit patterns in the substrate and on the surface form a three-dimensional transmission line structure in a 2-level ladder form of 'band-ground coplanar waveguide-similar coaxial-band-ground coplanar waveguide', thereby manufacturing the multilayer wiring ceramic substrate comprising the radio frequency signal input/output interface circuit patterns and the electrical connection pattern 20.

The metal enclosure frame 40 and the multilayer wiring ceramic substrate are brazed together through the solder 30 to form a hermetic sealing cavity;

after the assembly of various active devices on the multilayer wiring ceramic substrate is completed, the metal enclosure frame 40 is covered by the metal cover plate 50 through parallel seal welding or tin welding, and the radio frequency SiP ceramic package shell is manufactured.

The technical solution of the present invention will be further clearly described with reference to the accompanying drawings and specific examples.

Example 1

The structure of the radio frequency SiP ceramic package casing in the embodiment is shown in fig. 2, and the specific manufacturing method is as follows:

on 8 layers of LTCC green ceramic, each layer adopts thick film technology screen printing to manufacture interconnection through holes, circuit wiring and electrical connection patterns 20 according to design patterns, specifically, the designed electrical connection patterns 20 are printed on 3 rd layer green ceramic and 7 th layer green ceramic, and 4 designed coaxial transmission lines 70 are connected with 2 strip line transmission lines 60 on 5 th layer by screen printing in pairs;

laminating 8 layers of LTCC green ceramic chips printed with patterns according to a design sequence to form a substrate green body, carrying out heat preservation and sintering at 850 ℃ in the air for 10 minutes, then cooling to room temperature, and cutting to form a multilayer wiring ceramic substrate 80 which has the external dimension of 9mm multiplied by 0.8mm and comprises a radio frequency signal input/output interface circuit pattern and an electrical connection pattern 20, wherein the radio frequency signal input/output interface circuit pattern is an impedance matching transmission line structure in a 2-level ladder form of 'band-to-ground coplanar waveguide-similar coaxial-band line-similar coaxial-band-to-ground coplanar waveguide' shown in figure 1;

soldering a 4J29 alloy metal enclosure frame 40 with the overall dimension of 8.5mm multiplied by 0.6mm and the surface coated with nickel and gold film layers with a gold-tin alloy solder 30 for a multilayer wiring ceramic substrate in nitrogen at the temperature of 350 ℃ to form a hermetic sealing cavity;

and finally, after assembling various active devices in a cavity formed by the multilayer wiring ceramic substrate and the metal enclosure frame 40, welding 1 4J29 alloy metal cover plate 50 with the overall dimension of 8.5mm multiplied by 0.2mm and the surface coated with a nickel and gold film layer with the metal enclosure frame 40 in a parallel sealing and welding mode to manufacture the radio frequency SiP ceramic packaging shell.

Example 2

The structure of the radio frequency SiP ceramic package casing in the embodiment is shown in fig. 2, and the specific manufacturing method is as follows:

on 12 layers of aluminum nitride green ceramic wafers, each layer is printed with interconnection through holes, circuit wiring and electrical connection patterns 20 by a thick film process according to a design pattern. Printing designed electrical connection patterns 20 on the green porcelain sheets of the 3 rd layer and the 11 th layer, wherein 4 designed coaxial transmission lines 70 are connected with 2 strip line transmission lines 60 on the 7 th layer in pairs through screen printing;

then, the 12 layers of the aluminum nitride green ceramic chips printed with the patterns are laminated according to the design sequence to form a substrate green body, the substrate green body is subjected to heat preservation sintering at 1800 ℃ in nitrogen for 4 hours, then the temperature is reduced to the room temperature, and the multilayer wiring ceramic substrate which is 20mm multiplied by 1.8mm in external dimension and contains a radio frequency signal input/output interface circuit pattern and an electrical connection pattern 20 is manufactured by cutting, wherein the radio frequency signal input/output interface circuit pattern is an impedance matching transmission line structure which is shown in figure 1 and has a 2-level ladder form of 'band-to-ground coplanar waveguide-similar coaxial-band line-band-to-ground coplanar waveguide';

2 4J42 alloy metal surrounding frames 40 with the overall dimension of 8.5mm multiplied by 0.6mm and the surfaces of which are plated with nickel and gold film layers are brazed with a gold-germanium alloy solder 30 for a multilayer wiring ceramic substrate in nitrogen at the temperature of 430 ℃ to form 2 airtight cavities;

finally, after assembling various active devices on the multilayer wiring ceramic substrate, welding 2 4J42 alloy metal cover plates 50 with the overall dimension of 8.5mm multiplied by 0.2mm and the surfaces of which are plated with nickel and gold film layers with the metal surrounding frame 40 welded on the multilayer wiring ceramic substrate together in a soldering mode to finally manufacture the radio frequency SiP ceramic packaging shell.

Comparative example

Compared with the embodiment 1, the transmission line structure in the comparative example adopts a 1-step transmission line structure of coplanar waveguide-coaxial-coplanar waveguide, and the rest is the same as the embodiment 1 (including the number of layers, the thickness, the diameter of a through hole and the like of a multilayer wiring ceramic substrate), and the radio frequency SiP ceramic packaging shell structure manufactured by the transmission line structure is shown in fig. 4.

Test example

The radio frequency SiP ceramic package housings in example 1 and the comparative example were subjected to a hermetic test and a radio frequency input/output interface transmission insertion loss test, respectively.

The hermeticity test was performed according to method 1014 of GJB548 microelectronic device test methods and procedures.

The radio frequency I/O interface transmission insertion loss test uses 2 microwave probes with corresponding sizes to be respectively pressed on the coplanar waveguide transmission lines 10 on the upper surface and the lower surface of the multilayer ceramic substrate 80 (note that, in the comparative example, 1 microwave probe is pressed on the coplanar waveguide transmission line 10 on the upper surface of the multilayer ceramic substrate 80, and the other 1 microwave probe is pressed on the metal sheet 9 welded on the surface layer of the coplanar waveguide transmission line 10 on the lower surface of the multilayer ceramic substrate 80), a vector network analyzer connected with the microwave probes is used for testing S parameters of the transmission line structure, and S displayed by the instrument₂₁The value is the transmission insertion loss.

TABLE 1 radio frequency SiP ceramic package case Performance test results

	Air tightness	Transmission insertion loss
			Example 1	R1＝0.9×10-9Pa·m3/s	[email protected]
Comparative example	R1＝0.9×10-9Pa·m3/s	[email protected]

It can be seen from the comparison in table 1 that the 2-step transmission line structure of the 'strip-ground coplanar waveguide-like coaxial-strip line-like coaxial-strip-ground coplanar waveguide' is adopted in the invention, so that the radio frequency signal transmission insertion loss can be obviously reduced while the air tightness of the packaging shell is ensured. In addition, the radio frequency SiP ceramic packaging shell can realize the sealing of the packaging shell without welding a metal sheet at the bottom, thereby not only improving the air tightness of the packaging shell, but also simplifying the manufacturing process steps of the radio frequency SiP ceramic packaging shell, reducing the weight of the packaging shell, reducing the size of the packaging shell and realizing the light weight and miniaturization of the radio frequency SiP ceramic packaging shell.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.