阅读说明：本技术 分腔电磁屏蔽封装方法及封装结构 (Cavity-divided electromagnetic shielding packaging method and packaging structure ) 是由 李骞 陈建超 王海升 于 2020-04-30 设计创作，主要内容包括：本发明公开了一种分腔电磁屏蔽封装方法,包括以下步骤：提供一基板,在所述基板上安装多个芯片,对所述基板进行塑封,以形成包覆多个所述芯片的塑封层；提供具有清洗装置的划片机,采用所述划片机上的刀片对所述塑封层切割,以在相邻两个所述芯片之间形成沟槽,并采用所述清洗装置同时对所述沟槽清洗；在所述沟槽内填充导电材料,以形成第一屏蔽层；对所述基板和塑封层进行切割,以形成多个独立的封装结构。本发明使用具有清洗装置的划片机代替激光镭射技术形成用于分腔电磁屏蔽的沟槽,刀片切割和清洗同时进行,简化了步骤且提高了封装效率。(The invention discloses a sub-cavity electromagnetic shielding packaging method, which comprises the following steps: providing a substrate, mounting a plurality of chips on the substrate, and plastically packaging the substrate to form a plastic packaging layer for coating the plurality of chips; providing a dicing saw with a cleaning device, cutting the plastic package layer by using a blade on the dicing saw to form a groove between two adjacent chips, and cleaning the groove simultaneously by using the cleaning device; filling a conductive material in the groove to form a first shielding layer; and cutting the substrate and the plastic packaging layer to form a plurality of independent packaging structures. According to the invention, the scribing machine with the cleaning device is used for replacing a laser technology to form the groove for cavity electromagnetic shielding, and the cutting and cleaning of the blade are carried out simultaneously, so that the steps are simplified and the packaging efficiency is improved.)

1. A method for packaging a cavity-divided electromagnetic shielding is characterized by comprising the following steps:

providing a substrate, mounting a plurality of chips on the substrate, and plastically packaging the substrate to form a plastic packaging layer for coating the plurality of chips;

providing a dicing saw with a cleaning device, cutting the plastic package layer by using a blade on the dicing saw to form a groove between two adjacent chips, and cleaning the groove simultaneously by using the cleaning device;

filling a conductive material in the groove to form a first shielding layer;

and cutting the substrate and the plastic packaging layer to form a plurality of independent packaging structures.

2. The method for encapsulating an electromagnetic shielding cavity according to claim 1, wherein the step of providing a dicing saw with a cleaning device, cutting the molding compound layer with a blade on the dicing saw to form a groove between two adjacent chips, and simultaneously cleaning the groove with the cleaning device comprises:

installing a blade with a first thickness value on the dicing saw, and cutting the plastic package layer to form a first groove;

replacing the blade of the second thickness value, cutting along the bottom of the first groove to form a second groove;

wherein the second thickness value is smaller than the first thickness value, and the bottom of the second groove exposes the ground pad of the substrate.

3. The method for encapsulating an electromagnetic shielding cavity according to claim 1, wherein the step of providing a dicing saw with a cleaning device, cutting the molding compound layer with a blade on the dicing saw to form a groove between two adjacent chips, and simultaneously cleaning the groove with the cleaning device comprises:

installing a blade with a first thickness value on the dicing saw, and cutting the plastic package layer to form a first groove;

replacing the blade of the second thickness value, cutting along the bottom of the first groove to form a second groove;

replacing the blade of the third thickness value, cutting along the bottom of the second groove to form a third groove;

the first thickness value is greater than the second thickness value, the second thickness value is greater than the third thickness value, and the bottom of the third groove exposes the ground pad of the substrate.

4. The method of claim 1, wherein the dicing saw is a twin-axis dicing saw.

5. The method according to any of claims 1 to 4, wherein the step of cutting the substrate and the molding layer to form a plurality of individual package structures further comprises:

and sputtering a conductive material on the surface of the plastic packaging layer of the packaging structure to form a second shielding layer.

6. A packaging structure, characterized in that, the packaging structure is prepared by the cavity-divided electromagnetic shielding packaging method of any one of claims 1 to 5.

7. The package structure of claim 6, wherein the trench has a trench width of 15-90 μm.

8. The package structure of claim 6, wherein the trench has a width that gradually increases from the bottom of the trench toward the notch.

9. The package structure of claim 6, wherein a ratio of a trench depth to a trench width of the trench is 10:1 to 20: 1.

10. The package structure according to any one of claims 6 to 9, wherein the package structure is an SIP package structure.

Technical Field

The invention relates to the field of semiconductor packaging, in particular to a cavity-divided electromagnetic shielding packaging method and a cavity-divided electromagnetic shielding packaging structure.

Background

With the increasing integration density of packaged modules and the increasing complexity of products, the shielding technology for metalizing the surface of the product can only solve the problem of electromagnetic interference between modules, but cannot meet the problem of electromagnetic interference between chips inside the modules, so that mainstream manufacturers develop related cavity-separated shielding technologies.

At present, the cavity-dividing shielding technology is basically that after plastic packaging is finished, grooves are dug between chips needing shielding by laser, then conductive materials are filled between plastic packaging materials, and then the chips are cut into single products. At present, a cavity-dividing shielding technology is generally used for slotting by adopting a laser technology, a lot of dust exists in the slot, a conductive material is refilled after the slot is cleaned, the slot is generally cleaned by dry ice, but the operation is complex and the packaging efficiency is low.

Disclosure of Invention

The invention mainly aims to provide a sub-cavity electromagnetic shielding packaging method and a sub-cavity electromagnetic shielding packaging structure, and aims to solve the problems of complex operation and low efficiency of the conventional sub-cavity electromagnetic shielding packaging method.

In order to achieve the purpose, the invention provides a sub-cavity electromagnetic shielding packaging method, which comprises the following steps:

providing a substrate, mounting a plurality of chips on the substrate, and plastically packaging the substrate to form a plastic packaging layer for coating the plurality of chips;

providing a dicing saw with a cleaning device, cutting the plastic package layer by using a blade on the dicing saw to form a groove between two adjacent chips, and cleaning the groove simultaneously by using the cleaning device;

filling a conductive material in the groove to form a first shielding layer;

and cutting the substrate and the plastic packaging layer to form a plurality of independent packaging structures.

Preferably, the step of providing a dicing saw with a cleaning device, cutting the molding compound layer with a blade on the dicing saw to form a groove between two adjacent chips, and cleaning and washing the groove with the cleaning device simultaneously comprises:

installing a blade with a first thickness value on the dicing saw, and cutting the plastic package layer to form a first groove;

replacing the blade of the second thickness value, cutting along the bottom of the first groove to form a second groove;

wherein the second thickness value is smaller than the first thickness value, and the bottom of the second groove exposes the ground pad of the substrate.

Preferably, the step of providing a dicing saw with a cleaning device, cutting the molding compound layer with a blade on the dicing saw to form a groove between two adjacent chips, and cleaning and washing the groove with the cleaning device simultaneously comprises:

installing a blade with a first thickness value on the dicing saw, and cutting the plastic package layer to form a first groove;

replacing the blade of the second thickness value, cutting along the bottom of the first groove to form a second groove;

replacing the blade of the third thickness value, cutting along the bottom of the second groove to form a third groove;

the first thickness value is greater than the second thickness value, the second thickness value is greater than the third thickness value, and the bottom of the third groove exposes the ground pad of the substrate.

Preferably, the dicing saw is a biaxial dicing saw.

Preferably, the step of cutting the substrate and the molding compound layer to form a plurality of independent package structures further includes:

and sputtering a conductive material on the surface of the plastic packaging layer of the packaging structure to form a second shielding layer.

In addition, the invention also provides a packaging structure which is prepared by the cavity-dividing electromagnetic shielding packaging method.

Preferably, the groove width of the groove is 15-90 μm.

Preferably, the groove width of the groove gradually increases from the groove bottom to the notch.

Preferably, the ratio of the groove depth to the groove width of the groove is 10:1 to 20: 1.

Preferably, the package structure is a SIP package structure.

According to the technical scheme, a plurality of chips are mounted on a substrate, a plastic package layer for protecting the chips is prepared, a scribing machine with a cleaning device is used for cutting the plastic package layer to form a groove, the cleaning device is used for cleaning the groove during cutting, then a conductive material is filled in the groove to form a first shielding layer, and finally the whole substrate and the plastic package layer are cut to obtain a plurality of independent single packaging structures. According to the invention, the scribing machine with the cleaning device is used for replacing a laser technology to form the groove for cavity electromagnetic shielding, and the cutting and cleaning of the blade are carried out simultaneously, so that the steps are simplified and the packaging efficiency is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a step of a method for encapsulating a cavity-divided electromagnetic shield according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a package structure according to an embodiment of the invention;

fig. 3 is a schematic structural diagram of a package structure according to another embodiment of the invention;

FIG. 4 is a schematic structural diagram of a package structure according to yet another embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a package structure according to yet another embodiment of the present invention;

fig. 6 is a schematic partial structural diagram of a dicing saw in the method for encapsulating a cavity-divided electromagnetic shielding according to an embodiment of the present invention;

fig. 7 is a flowchart of a method for encapsulating a cavity-divided electromagnetic shield according to an embodiment of the invention.

The reference numbers illustrate:

1	substrate	11	Grounding pad
				2	Chip and method for manufacturing the same	3	Plastic packaging layer
4	Groove	41	The first groove
				42	Second groove	43	Third groove
5	Blade	61	Blade mounting shaft
				62	Cleaning water outlet	63	Cooling water outlet

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In addition, the technical solutions in the embodiments of the present invention may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination of technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

In addition, the present invention provides a first embodiment of a method for encapsulating a cavity-separated electromagnetic shielding, as shown in fig. 1, fig. 2, fig. 6 and fig. 7, including the following steps:

s10, providing a substrate 1, mounting a plurality of chips 2 on the substrate 1, and plastically packaging the substrate 1 to form a plastic packaging layer 3 for coating the chips 2;

the molding layer 3 is used to protect the chip 2 and prevent the electrical performance of the chip 2 from being degraded due to the corrosion of the circuit of the chip 2 caused by impurities in the air.

S20, providing a dicing saw with a cleaning device, cutting the plastic package layer 3 by using a blade 5 on the dicing saw to form a groove 4 between two adjacent chips 2, and cleaning the groove 4 by using the cleaning device;

the dicing saw of the present embodiment refers to a dicing saw having a cleaning function and mounted with a blade 5, such as a wafer dicing saw or a substrate dicing saw, the working principle of the dicing saw is a powerful cutting, when a workpiece is cut, a blade mounting shaft 61 of the dicing saw descends along a Z axis, the workpiece is pushed to move in a direction of the blade 5, the blade 5 rotating at a high speed is driven to cut the workpiece, and a cleaning device on the dicing saw includes a cleaning water outlet 62 for spraying cleaning water from a radial direction to the bottom of the blade 5 to wash waste materials generated during the working process of the dicing saw. The dicing saw is also provided with a cooling water outlet 63, because the blade 5 can generate a large amount of heat when the blade 5 is used for dicing a workpiece in the working process of the dicing saw, the temperature of the blade 5 and the workpiece to be processed can be rapidly increased, the dicing quality can be seriously affected by overhigh temperature, the service life of the blade 5 can be greatly shortened, and in order to reduce the temperature of the blade 5 and the workpiece to be processed, the blade 5 and the workpiece need to be cooled by spraying cooling water in the dicing process. The specific steps of cutting the groove 4 are as follows: the method comprises the steps of determining the size of a target groove 4, determining the specification of a slotting blade 5, determining parameters such as initial slotting position, stepping, speed and depth, establishing a cutting and cleaning program, establishing a target identification program, feeding, starting automatic cutting and cleaning, and finishing the processing of the groove 4. The present embodiment can adopt a full-automatic dicing saw with model number AD3000T or DFD6361, and since the dicing saw is an existing device, the working principle of the dicing saw is known from the common general knowledge of those skilled in the art, and therefore, the description thereof is not expanded.

The accumulated cutting offset error of the embodiment is less than 2 microns, the Z-direction positioning is accurate, the error is less than 1 micron, the cutting offset can be accurately cut to the surface of the grounding pad 11 of the substrate 1, and the cutting offset has higher cutting accuracy and smaller offset error compared with a laser process; the section of cutting plastic envelope layer 3 is level and smooth, is favorable to follow-up conductive material's packing, and this embodiment accomplishes 5 cutting of blade and the washing of slot 4 simultaneously, and easy operation has improved encapsulation efficiency.

S30, filling a conductive material in the groove 4 to form a first shielding layer;

the conductive material can be silver paste or copper paste, and after the filled conductive material is cured at high temperature, a first shielding layer is formed to prevent electromagnetic interference between the chips 2.

And S40, cutting the substrate 1 and the plastic package layer 3 to form a plurality of independent packaging structures.

Through installing the repetitive unit of a plurality of encapsulation modules on base plate 1 earlier to cutting a plurality of slots 4, cutting into a plurality of independent individual packaging structure again at last, can improve production efficiency.

According to a second embodiment of the cavity-divided electromagnetic shielding packaging method proposed by the first embodiment of the present invention, as shown in fig. 3, a dicing saw with a cleaning device is provided, the dicing saw cuts the molding compound layer 3 by using a blade 5 on the dicing saw to form a trench 4 between two adjacent chips 2, and the step of simultaneously cleaning the trench 4 by using the cleaning device comprises:

installing a blade 5 with a first thickness value on a dicing saw, and cutting the plastic package layer 3 to form a first groove 41;

replacing the blade 5 of the second thickness value, cutting along the bottom of the first groove 41 to form a second groove 42;

wherein, the second thickness value is smaller than the first thickness value, and the bottom of the second groove 42 exposes the ground pad 11 of the substrate 1.

In the embodiment, a step cut cutting mode is adopted, a wider groove is formed by adopting a wider blade 5, a narrower groove 4 is formed by using a narrower blade 5 on the basis of the groove, and the T-shaped groove 4 is cut.

According to a third embodiment of the cavity-divided electromagnetic shielding packaging method proposed by the first embodiment of the present invention, as shown in fig. 4, a dicing saw with a cleaning device is provided, a blade 5 on the dicing saw is used to cut the plastic package layer 3 to form a trench 4 between two adjacent chips 2, and the step of simultaneously cleaning the trench 4 with the cleaning device includes:

installing a blade 5 with a first thickness value on a dicing saw, and cutting the plastic package layer 3 to form a first groove 41;

replacing the blade 5 of the second thickness value, cutting along the bottom of the first groove 41 to form a second groove 42;

replacing the blade 5 of the third thickness value, cutting along the bottom of the second groove 42 to form a third groove 43;

the first thickness value is greater than the second thickness value, the second thickness value is greater than the third thickness value, and the bottom of the third groove 43 exposes the ground pad 11 of the substrate 1.

In the embodiment, a step cut cutting mode is adopted to cut the stepped groove 4, the width of the third groove 43 is small, the distance between the chips 2 can be reduced, and the size of the packaging structure is reduced; the width of the first groove 41 is large, so that conductive materials can be conveniently injected; the width of the second groove 42 is between the width of the first groove 41 and the width of the third groove 43, which facilitates the conductive material to flow into the groove bottom and also allows space for the chip 2 or other components.

In a fourth embodiment of the cavity-divided electromagnetic shielding packaging method according to the first embodiment of the present invention, the dicing saw is a biaxial dicing saw. Two blades 5 of biax scriber mountable realize that the double knives is processed simultaneously, can cut out two slots 4 simultaneously, have improved cutting efficiency.

In a fifth embodiment of the method for packaging an electromagnetic shielding package with separated cavities according to the first embodiment of the present invention, the step of cutting the substrate 1 and the molding layer 3 to form a plurality of independent package structures further includes:

and sputtering a conductive material on the surface of the plastic packaging layer 3 of the packaging structure to form a second shielding layer.

In this embodiment, a conductive material is sputtered on five surfaces (a front surface + four side surfaces) of a single package structure, so as to form a conformal shield, thereby preventing the package structure from being subjected to external electromagnetic interference.

In addition, the invention also provides a packaging structure which is prepared by the cavity-divided electromagnetic shielding packaging method. Since the package structure adopts all the technical solutions of all the embodiments, at least all the beneficial effects brought by the technical solutions of the embodiments are achieved, and no further description is given here.

Further, the groove width of the groove 4 is 15 to 90 μm. Because the cutting blade 5 has wide size and width and the minimum thickness can reach 15 micrometers, the ultra-small-size slotting of 15-20 micrometers can be realized, and the laser process can only open the groove 4 of 60-90 micrometers at minimum. Therefore, the width of the groove 4 of the present embodiment is narrower than that of the groove 4 cut by the laser process, and the size of the package structure can be reduced.

In another embodiment, the groove width of the groove 4 increases gradually from the groove bottom to the notch. Different types of groove shapes can be cut by using blades 5 with different shapes, for example, a blade 5 with a circular cross section is used for cutting, and a groove 4 as shown in fig. 2 can be obtained; the replacement of the blade 5 also results in a V-shaped groove 4 as shown (as shown in fig. 5); t-shaped or step-shaped trenches 4 (as shown in fig. 3 and 4) can also be obtained by a "step cut" cutting mode. The groove 4 with the wider opening facilitates the injection of the conductive material, and can shorten the distance between the adjacent chips 2 and reduce the size of the packaging structure.

The blade 5 is mounted on the blade mounting shaft 61, the position of the blade mounting shaft 61 can be adjusted along the Z axis, the position of the blade mounting shaft 61 on the Z axis can be determined according to the depth of the target groove 4, and according to the relation between the elongation of the blade 5 and the thickness of the blade 5, the ratio of the groove depth to the groove width of the groove 4 can be 10: 1-20: 1. The ratio of the groove depth to the groove width of the groove 4 cut by the laser process can only reach 10: 1.

the Package structure of the present embodiment is a System In Package (SIP) Package structure. The SIP package is a package in which a plurality of functional chips 2, including functional chips 2 such as a processor and a memory, are integrated, thereby implementing a substantially complete function. By arranging the first shielding layer between the adjacent chips 2, the cavity-divided electromagnetic shielding of the SIP package is formed, and the mutual interference between different chips 2 in the SIP package is avoided.

The above is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent changes made by the present specification or directly/indirectly applied to other related technical fields under the spirit of the present invention are included in the scope of the present invention.