Disclosure of Invention
At least to overcome one of the above-mentioned drawbacks, the present invention provides a three-dimensional airtight packaging structure and a packaging method, which improve the precision and airtight effect of packaging and simplify the packaging process by improving the cooperation between the packaging enclosure and the microcolumns between the packaging substrates.
In order to achieve the above object, the package structure disclosed by the invention may adopt the following technical scheme:
a three-dimensional hermetic package structure, comprising:
The chip module is arranged on the opposite surfaces of the top packaging substrate and the bottom packaging substrate, and interconnection interfaces are arranged on the opposite surfaces of the top packaging substrate and the bottom packaging substrate;
The combined enclosing frame structure is arranged between the top packaging substrate and the bottom packaging substrate to form an airtight structure and comprises a limiting piece and an enclosing frame piece which are correspondingly arranged on the top packaging substrate and the bottom packaging substrate and are in opposite fit, and an opposite fit surface of the limiting piece and the enclosing frame piece is provided with an opposite fit structure;
The microcolumn structure arranged between the top packaging substrate and the bottom packaging substrate comprises microcolumns and microcolumns which are in conductive fit, wherein the microcolumns and the microcolumns are conductive to the top packaging substrate and the bottom packaging substrate.
The three-dimensional airtight packaging structure disclosed by the invention has the advantages that the top packaging substrate and the bottom packaging substrate are aligned and matched in a combined enclosing frame structure to form accurate alignment, so that the mounting precision is improved, meanwhile, the micro-column structure arranged between the top packaging substrate and the bottom packaging substrate can be conducted, the height of the micro-column structure is the same as that of the combined enclosing frame structure, and the top packaging substrate and the bottom packaging substrate can be kept well in contact sealing after aligned and matched. The airtight packaging structure disclosed by the invention can be used for synchronously welding and sealing after being integrally assembled, so that the requirements of precision welding on high size requirements and difficulty in ensuring welding quality are avoided, and the heating welding treatment can be synchronously carried out, thereby realizing the molding of the whole airtight packaging structure.
Furthermore, the chip module is arranged in the packaging cavity and is subjected to anti-interference shielding treatment, the anti-interference of the chip can be realized in various modes, the chip module is not limited only, and one of the possible choices is optimally selected, wherein the chip module comprises a chip, a chip welding layer for welding the chip to a top packaging substrate or a bottom packaging substrate, and a shielding piece for shielding the chip, and an air gap is formed between the shielding piece and the chip. When the scheme is adopted, the top packaging substrate and the bottom packaging substrate are both provided with chips, the chips are fixedly connected through a chip welding layer, and the shielding piece is a cover body in a cover shape and is fixedly connected to the outer side of the chips through welding flux and used for sealing.
Further, in the invention, the alignment matching structure is used for aligning the frame surrounding piece and the limiting piece, so that the frame surrounding piece can form a closed cavity at the top packaging substrate and the bottom packaging substrate, the scheme adopted by the alignment matching structure is not limited only, optimization is carried out and one feasible choice is given here, the alignment matching structure comprises a concave structure and a convex structure, when the limiting piece is aligned and matched with the frame surrounding piece, the concave structure and the convex structure are tightly clamped and attached, and an airtight connecting layer is further arranged between the concave structure and the convex structure. When the scheme is adopted, the concave structure and the convex structure form the zigzag, V-shaped or zigzag splicing surfaces, and the top packaging substrate and the bottom packaging substrate can be aligned fast through the accurate matching of the splicing surfaces, so that the connection accuracy is ensured, and the connection efficiency is also ensured.
Furthermore, in order to more stably set the combined surrounding frame structure, the mounting structure is optimally set and one of the feasible choices is given out, wherein the bottom packaging substrate is correspondingly provided with a connecting conduction seat. When the scheme is adopted, the connecting conduction seat and the combined enclosing frame structure can be connected in a sealing way through solder.
Further, the micro-pillars are used to connect the top package substrate and the bottom package substrate, but the scheme is not limited to only, and the micro-pillars extend from the bottom package substrate to the top package substrate, and the micro-solder balls are connected and matched with the top ends of the micro-pillars.
Still further, the arrangement mode of the micro-column structure is optimized and one of the possible choices is selected, wherein the top packaging substrate and the bottom packaging substrate are respectively provided with a connecting and conducting seat, and the micro-column and the micro-solder ball conduct the top packaging substrate and the bottom packaging substrate through the connecting and conducting seats. When the scheme is adopted, the micro-cylinder is connected and fixed with the connecting and conducting seat, and then signal conduction can be realized.
The airtight packaging structure is described, and the scheme for realizing the airtight packaging is also disclosed, and is now described.
A three-dimensional hermetic packaging method for preparing the hermetic packaging structure described above, comprising:
a connecting conducting seat is correspondingly arranged on the top packaging substrate and the bottom packaging substrate;
A limiting piece and a surrounding frame piece are correspondingly arranged on the top packaging substrate and the bottom packaging substrate respectively, wherein the surrounding frame piece and the micro-column structure are synchronously arranged, the end surfaces of the surrounding frame piece and the micro-column structure are flush, and an airtight welding material layer is arranged on the opposite matching surfaces of the limiting piece and/or the surrounding frame piece;
Fixing the micro solder balls on the end faces of the micro cylinders;
and at least correspondingly connecting and fixing the chips on the top packaging substrate and the bottom packaging substrate;
The opposite matching surfaces of the limiting piece and the surrounding frame piece are spliced, the upper end face of the top packaging substrate is heated and pressurized to carry out airtight welding, the micro-column structure is synchronously welded to conduct the top packaging substrate and the bottom packaging substrate, and vacuum is pumped into the packaging cavity in the welding process.
According to the packaging method, after the combined enclosing frame structure of the top packaging substrate and the bottom packaging substrate is set, the combined enclosing frame structure can be used for alignment and limit matching, and the synchronous arrangement of the enclosing frame piece and the micro-column structure can keep the end faces of the enclosing frame piece and the micro-column structure flush, so that the accuracy is improved in the process of arranging the airtight structure. According to the packaging method, after the top packaging substrate and the bottom packaging substrate are spliced, the connection is realized through integral heating, and the problem that the reliability of the packaging structure is affected by stress caused by local temperature difference caused by a point-by-point welding mode of laser and the like is avoided.
Furthermore, when preparing the frame surrounding piece and the micro-column, the frame surrounding piece and the micro-column are synchronously prepared and separated after connection, and the method is particularly optimized and comprises the following feasible modes that the frame surrounding piece and the micro-column are integrally connected by processing a piece of flat plate material by adopting a material reduction method, one plane of the flat plate material is used as the end face of the frame surrounding piece and the micro-column, a removable process line structure is arranged at the connection part of the frame surrounding piece and the micro-column, and after the frame surrounding piece and the micro-column are connected and fixed to the top packaging substrate or the bottom packaging substrate, the process line structure is removed to separate the frame surrounding piece and the micro-column. When the scheme is adopted, the enclosure frame piece and the micro-column body are integrally processed, the consistent connection height can be kept after connection and fixation, the connection and fixation of the top packaging substrate and the bottom packaging substrate are facilitated, and the dimensional precision of the top packaging substrate and the bottom packaging substrate can be kept after connection.
Further, in order to perform better airtight welding, the surfaces of the frame surrounding piece and the micro-column structure are processed, and optimization is performed and one of the possible choices is given here, namely plating layers are respectively arranged on the outer surfaces of the frame surrounding piece and the micro-column after the frame surrounding piece and the micro-column are processed. Still further, the order of the arrangement of the chip modules is not limited only, for example, in some cases, the chip and the shielding member may be set at the same time, in some cases, the chip and the shielding member may be set separately, and optimization is performed herein, and one possible option is to set the shielding member and cover the chip after the limiting member and the frame surrounding member are set.
Compared with the prior art, the technical scheme disclosed by the invention has the following partial beneficial effects:
The invention prepares the frame surrounding piece and the micro-column structure together, the size control of the frame surrounding piece and the micro-column structure is more accurate, the height consistency can be controlled in the micron level, and the requirements of the interconnection height and the encapsulation air tightness of the integrated chips on the upper surface and the lower surface in the encapsulation are met. Through the relative mating surface structure between the limiting piece and the surrounding frame piece, the alignment efficiency of the top packaging substrate and the bottom packaging substrate is improved, and complicated high-precision alignment operation is avoided. The packaging structure provided by the invention has the advantages of high precision, simple packaging procedure and flexible and convenient operation.
Detailed Description
The invention is further illustrated by the following description of specific embodiments in conjunction with the accompanying drawings.
Aiming at the conditions of complicated high-precision alignment procedure and unsatisfactory packaging effect of the packaged chip in the prior art, the following embodiment optimizes and overcomes the problems in the prior art.
Example 1
As shown in fig. 1 to 5, the present embodiment provides a three-dimensional airtight packaging structure, which aims to improve the alignment precision of the packaging mechanism, ensure the reliability of airtight packaging, and improve the convenience of alignment packaging.
As the airtight package structure provided in the present embodiment, one of the structures includes:
the chip modules are arranged on opposite surfaces of the top packaging substrate 1 and the bottom packaging substrate 8, and interconnection interfaces are arranged on opposite surfaces of the top packaging substrate 1 and the bottom packaging substrate 8.
Preferably, in this embodiment, the interconnection interface is a BGA interface.
The top package substrate 1 and the bottom package substrate 8 may be ceramic package substrates.
In this embodiment, the chip module is disposed in the package cavity and performs anti-interference shielding treatment, so that anti-interference of the chip can be achieved in a plurality of ways, and this embodiment is not limited to the only way, and is optimized and one of the possible choices is adopted, where the chip module includes a chip 6, a chip solder layer 5 for soldering the chip 6 to the top package substrate 1 or the bottom package substrate 8, and a shielding member 7 for covering the chip 6 to shield interference, and an air gap is formed between the shielding member 7 and the chip 6. With such a scheme, the top package substrate 1 and the bottom package substrate 8 are both provided with the chip 6, the chip 6 is fixedly connected by the chip solder layer 5, and the shielding member 7 is a cover-shaped cover body which is fixedly connected to the outside of the chip 6 by solder and seals.
Preferably, the die pad 5 used in the present embodiment includes a structure formed by sintering nano silver.
As the airtight package structure provided in this embodiment, the second structure includes:
The combined enclosure frame structure is arranged between the top packaging substrate 1 and the bottom packaging substrate 8 to form an airtight structure, and comprises a limiting part 3 and an enclosure frame part 9 which are correspondingly arranged on the top packaging substrate 1 and the bottom packaging substrate 8 and are matched relatively, and a counterpoint matching structure is arranged on the opposite matching surface of the limiting part 3 and the enclosure frame part 9.
Preferably, the enclosure frame 9 in the present embodiment is disposed on the bottom package substrate 8, and the limiting member 3 is disposed on the top package substrate 1. And the opposite matching surfaces of the limiting piece 3 and the surrounding frame piece 9 form a step-shaped structure.
Preferably, in the present invention, the alignment structure is used to align the frame surrounding member 9 with the limiting member 3, so that the frame surrounding member 9 can enclose a closed cavity at the top packaging substrate 1 and the bottom packaging substrate 8, the scheme that the alignment structure can adopt is not limited only, the embodiment is optimized and one of the possible choices is adopted, the alignment structure includes a concave structure and a convex structure, when the limiting member 3 is aligned and matched with the frame surrounding member 9, the concave structure and the convex structure are tightly clamped and attached, and an airtight connecting layer is further provided between the concave structure and the convex structure. When the scheme is adopted, the concave structure and the convex structure form a Z-shaped, V-shaped or zigzag split surface, and the top packaging substrate 1 and the bottom packaging substrate 8 can be quickly aligned through the accurate matching of the split surfaces, so that the accuracy of connection is ensured, and the connection efficiency is also ensured.
Preferably, in this embodiment, the concave structure and the convex structure are matched to form a step shape, so as to realize alignment and positioning.
In this embodiment, the airtight connection layer is a solder layer, and after the heat and pressure treatment, the opposite mating surfaces are welded and sealed. The airtight connection layer adopts Au80Sn20 as a connection solder.
In this embodiment, in order to more stably set the combined enclosure frame structure, the mounting structure is optimally set and one of the possible choices is adopted, wherein the connection conduction seat 2 is arranged on the bottom packaging substrate 8 corresponding to the combined enclosure frame structure. When the scheme is adopted, the connecting conduction seat 2 and the combined enclosing frame structure can be connected in a sealing way through solder.
Preferably, the welding flux between the connecting conducting seat 2 and the combined surrounding frame structure can be made of Au80Sn20 alloy material.
As the airtight package structure provided in this embodiment, a third structure thereof includes:
The microcolumn structure arranged between the top packaging substrate 1 and the bottom packaging substrate 8 comprises microcolumns 10 and microcoball 11 which are in conductive fit, wherein the microcolumns 10 and the microcolumns 11 are conductive to the top packaging substrate 1 and the bottom packaging substrate 8.
The micro-pillars 10 are used to connect the top package substrate 1 and the bottom package substrate 8, the scheme is not limited, and the present embodiment is optimized and one of the possible options is that the micro-pillars 10 extend from the bottom package substrate 8 to the top package substrate 1, and the micro-solder balls 11 are connected to and matched with the top ends of the micro-pillars 10.
Preferably, the arrangement mode of the micro-column structure is optimized and one of the possible choices is adopted in the embodiment, wherein the top packaging substrate 1 and the bottom packaging substrate 8 are both provided with a connection conduction seat 2, and the micro-column 10 and the micro-solder ball 11 conduct the top packaging substrate 1 and the bottom packaging substrate 8 through the connection conduction seat 2. By adopting the scheme, the micro-cylinder 10 is fixedly connected with the connecting conduction seat 2, and then signal conduction can be realized.
Preferably, in the present embodiment, the frame member 9 and the micro-column 10 are made of metal materials, and the height is 1 mm-2 mm, and the flatness error of the end surfaces of the frame member 9 and the micro-column 10 is less than 5 μm.
Preferably, in this embodiment, the diameter of the micro solder ball 11 is greater than or equal to the diameter of the micro cylinder 10, and the matching requirement of the diameter of the micro solder ball 11 and the spacing member 3 (including the solder layer) is that after the micro solder ball 11 is preset on the upper surface of the micro cylinder 10, the distance between the top surface of the micro solder ball 11 and the upper surface of the micro cylinder 10 is H1, the thickness of the conductive connection seat on the top package substrate 1 is H2, the maximum distance between all the step surfaces of the spacing member 3 and the first soldering surface is D1, and the minimum distance is D2, then D1> h1+h2> D2.
The three-dimensional airtight packaging structure disclosed by the invention forms accurate alignment by combining the peripheral frame structure to form the alignment fit of the top packaging substrate 1 and the bottom packaging substrate 8, so that the mounting precision is improved, meanwhile, the micro-column structure arranged between the top packaging substrate 1 and the bottom packaging substrate 8 can realize conduction, and the height of the micro-column structure is the same as that of the combined peripheral frame structure, so that the top packaging substrate 1 and the bottom packaging substrate 8 can keep good contact seal after alignment fit. By adopting the airtight packaging structure disclosed by the embodiment, synchronous welding and sealing can be carried out after the whole assembly, the requirements of precision welding on high size requirements and difficulty in guaranteeing welding quality are avoided, and the heating welding treatment can be synchronously carried out, so that the molding of the whole airtight packaging structure is realized.
Example 2
The foregoing embodiments have described a hermetic package structure, and this embodiment also discloses a scheme for implementing the hermetic package, and will now be described.
As shown in fig. 6, a three-dimensional hermetic packaging method for preparing the hermetic packaging structure described above includes the following steps:
and S01, correspondingly arranging connection conducting seats 2 on the top packaging substrate 1 and the bottom packaging substrate 8.
S02, a limiting piece 3 and a surrounding frame piece 9 are correspondingly arranged on the top packaging substrate 1 and the bottom packaging substrate 8 respectively, wherein the surrounding frame piece 9 and the micro-column structure are synchronously arranged and have the end face flush, and an airtight welding layer is arranged on the opposite matching surfaces of the limiting piece 3 and/or the surrounding frame piece 9.
Specifically, the following steps are adopted when the limiting member 3 is arranged:
s021, arranging a limiting piece 3 on the peripheral position of the welding surface of the top packaging substrate 1 by a method of combining thick photoresist photoetching with electroplating.
And S022, arranging Au80Sn20 solder on the opposite matching surface of the limiting piece 3 by a micro-seam welding, electroplating or evaporating method to serve as an airtight connecting layer, wherein the thickness of the airtight connecting layer is 5-20 mu m.
S03, fixing the micro solder balls 11 to the end faces of the micro pillars 10.
Preferably, the laser ball-planting process is adopted to preset micro solder balls 11 on the upper surfaces of all the micro cylinders 10.
And S04, correspondingly connecting and fixing the chip 6 on the top packaging substrate 1 and the bottom packaging substrate 8.
The order of arrangement of the chip modules is not limited, and for example, the chip 6 and the shielding member 7 may be set simultaneously in some schemes, and may be set separately in some schemes, and this embodiment is optimized and adopts one of the possible choices that the shielding member 7 is set and the chip 6 is covered after the limiting member 3 and the frame member 9 are set.
Preferably, the chip and the shielding frame are mounted by nano silver sintering.
After the mounting of the chip 6 is completed, the shield 7 is mounted by a nano silver sintering process, and the shield 7 is configured in a cap shape to cover the chip 6.
S05, the opposite matching surfaces of the limiting piece 3 and the surrounding frame piece 9 are spliced, the upper end face of the top packaging substrate 1 is heated and pressurized to carry out airtight welding, the micro-column structure is synchronously welded to conduct the top packaging substrate 1 and the bottom packaging substrate 8, and vacuum is pumped in the packaging cavity in the welding process.
In the process of S05, the limiting member 3 and the surrounding frame member 9 form a three-dimensional airtight packaging structure through stacking welding.
Preferably, when preparing the enclosure frame 9 and the micro-column 10, the enclosure frame 9 and the micro-column 10 are prepared synchronously and separated after connection, and the enclosure frame 9 and the micro-column 10 are specifically optimized and obtained by processing a piece of flat plate material by adopting a material reduction method, wherein one plane of the flat plate material is used as the end face of the enclosure frame 9 and the micro-column 10, a removable process line structure is arranged at the connection position of the enclosure frame 9 and the micro-column 10, and after the enclosure frame 9 and the micro-column 10 are connected and fixed to the top packaging substrate 1 or the bottom packaging substrate 8, the process line structure is removed to separate the enclosure frame 9 and the micro-column 10. When the scheme is adopted, the enclosure frame 9 and the micro-column 10 are integrally processed, the consistent connection height can be kept after connection and fixation, the connection and fixation of the top packaging substrate 1 and the bottom packaging substrate 8 are facilitated, and the dimensional precision of the top packaging substrate 1 and the bottom packaging substrate 8 can be kept after connection.
The preparation of the frame surrounding piece 9 and the micro-column 10 specifically comprises the following steps:
and S051, providing a metal flat plate which is subjected to grinding and polishing to process materials of the frame surrounding piece 9 and the micro-cylinder 10, wherein the thickness of the metal flat plate is 1-2mm and is equal to the heights of the frame surrounding piece 9 and the micro-cylinder 10.
S052, removing redundant materials between the frame surrounding piece 9 and the micro-columns 10 from the upper surface of the metal flat plate by a water-guided laser cutting method, and processing a process line when the thickness of the process line is 0.3mm away from the bottom surface, wherein the process line is connected with the frame surrounding piece 9 and all the micro-columns 10 on the lower surface of the metal flat plate.
S053, processing the frame surrounding piece 9 from the lower surface of the metal flat plate by a water-guided laser cutting method.
S054, ni plating layers of 4-8 mu m and Au plating layers of 1-2 mu m are sequentially arranged on the outer surface of the composite structure of the surrounding frame piece 9 and the micro cylinder 10.
Preferably, a solder is provided as an airtight connection layer on the soldering surface of the bottom package substrate 8 by using a steel screen printing or evaporation method, and the solder is Au80Sn20 alloy for connecting the frame enclosure 9 and the micro-cylinder 10.
Preferably, the composite structure of the enclosure frame 9 and the micro-column 10 is welded on the welding surface of the bottom packaging substrate 8 by using vacuum eutectic welding or vacuum reflow welding, and the pressing blocks with flat plate structures are placed on the surfaces of the enclosure frame 9 and the micro-column 10 in the welding process, so that the process line plays a role in uniformly stressing at the same time and ensuring the height consistency of the enclosure frame and the metal micro-column after welding.
Preferably, after the connection and fixation of the frame member 9 and the micro-cylinder 10 are completed, the process line is removed using a water-guided laser cutting method.
According to the packaging method disclosed by the invention, after the combined enclosing frame structure of the top packaging substrate 1 and the bottom packaging substrate 8 is set, the combined enclosing frame structure can be used for aligning and limiting cooperation, and the synchronous arrangement of the enclosing frame piece 9 and the micro-column structure can keep the end surfaces of the two to be flush, so that the precision is improved in the process of arranging the airtight structure. According to the packaging method, after the top packaging substrate 1 and the bottom packaging substrate 8 are spliced, the connection is realized through integral heating, so that the reliability of the packaging structure is prevented from being influenced by local temperature difference caused by adopting a point-by-point welding mode.
The above is an embodiment exemplified in this example, but this example is not limited to the above-described alternative embodiments, and a person skilled in the art may obtain various other embodiments by any combination of the above-described embodiments, and any person may obtain various other embodiments in the light of this example. The above detailed description should not be construed as limiting the scope of the present embodiments, which is defined in the appended claims.