CN114826180A - Embedded structure of filter module and manufacturing method - Google Patents

Abstract

The utility model provides a bury structure of wave filter module, change the full device package of wave filter module into partial encapsulation and partly bury in the base plate, the conflict problem of filter cavity tectorial membrane and the abundant packing in flip-chip switch chip copper post space has been solved, the problem of the packing of inductance passive component interpolar space has been solved, the filter packaging body extremely has been solved and has been reduced the volume and cause the reliability hidden danger problem, it leads to the product to warp and the hidden danger of inefficacy to have solved the unbalance of multiple different material internal stress of full device package, the insufficient problem of the little epoxy packing in the intensive gap of components and parts has been solved. Meanwhile, different packaging schemes of the filter can be selected, and cost control of using a scheme of using a high-cost special film-coated material can be effectively reduced.

Description

Embedded structure of filter module and manufacturing method

Technical Field

The invention relates to the technical field of semiconductor radio frequency, in particular to a filter module integrated device of a signal receiving end.

Background

The current package structure:

the first method comprises the following steps: plastic packaging device of inner packaging filter of PiP (Package in Package) module device

The conventional external shape is lga (land Grid array) Grid array package, the internal planar structure is formed by mounting all components on a substrate (component carrier), and the arrangement of the components includes: a plurality of filter packaging bodies, a flip-chip switch chip, a plurality of inductance passive elements and the like. The filter packaging body is connected with the module substrate through tin solder, and the gaps of the components are filled with epoxy resin, so that the circuit isolation and protection effects are achieved.

The common structure of the filter packaging body is that a filter chip is arranged on a substrate in an inverted mode, and a layer of isolation film is attached to the upper portion of the chip, so that the IDT resonators on the surface of the filter chip are located in a cavity environment, and the function normal operation of the IDT resonators is guaranteed. And epoxy resin is filled above the isolation film to fill the gap and make the surface flat.

The advantages are that: after the switch chip and the substrate are filled with epoxy resin, no cavity stress is released, the circuit protection effect is good, and no cavity is formed between the two poles of the inductor passive element after the switch chip and the substrate are filled with epoxy resin, so that the circuit short circuit problem is caused.

The disadvantages are as follows: the filter has the problems that the area of a packaging body of the filter is large, the density of devices is high, the space (gap) between the devices is small, epoxy resin is easily insufficiently filled in the plastic packaging process, a cavity inside a module device is formed, short circuits between different circuit elements are easily caused, cracking is caused due to poor airtightness, the cavity absorbs water and vaporizes to cause the internal burst of the device, and the like. The size of the filter packaging body is reduced to the limit as a balance, the distance from a filter chip in the filter packaging body to the edge of the packaging body is reduced, the water vapor immersion blocking capacity of a filter covering film is reduced, and the secondary problem of reliability is further derived.

And the second method comprises the following steps: planar integrated mount, commonly in the form of lga (land grid array) grid array packages.

The internal planar structure is mainly arranged on a substrate (component carrier) in a planar manner, and a small number of chips and chip stacking forms are also provided. The arranging element includes: a plurality of filter chips, a flip switch chip, a plurality of inductance passive elements, etc.

The internal longitudinal surface structure is formed by attaching all the elements on the upper surface of the substrate. And an isolation film is pasted on all the elements, so that the IDT resonator on the surface of the filter chip is in a cavity environment, and the normal operation of the IDT resonator is ensured. And epoxy resin is filled above the isolation film to fill the gap and make the surface flat.

The advantages are that: compared with a PiP structure, the area and the volume of the filter chip are smaller than those of a filter packaging body, and the surface mounting space can be properly vacated.

The disadvantages are as follows: the device density is high, the device interval (gap) is small, epoxy resin is easily insufficiently filled in the plastic packaging process, a cavity in a module device is formed, cracking can be caused due to poor tightness, and the cavity absorbs water and vaporizes to cause the problems of internal bursting of the device and the like. And the whole coating can form a cavity between two electrodes of the passive element, so that the risk of short circuit of tin materials is high. A cavity is formed between the flip switch chip and the substrate, and the risk of short circuit of the solder material is also caused. Meanwhile, epoxy resin is not effectively filled between the flip switch chip and the substrate, and the stress of the module device is unbalanced under different environments, so that the joints of the copper column and the substrate, the copper column and the tin material, the copper column and the chip and the like are broken easily, and the circuit is failed.

As shown in fig. 6 and 7, the inductive passive element 10 is included, and the switch chip 8 is disposed outside the substrate.

Disclosure of Invention

For the problem that exists among the prior art of solving, this scheme changes the encapsulation of full device in the filter module into partial encapsulation and partly buries in the base plate, the conflict problem of filter cavity tectorial membrane and flip-chip switch chip copper post space fully filled has been solved, the problem of inductance passive component interelectrode space filling has been solved, the filter packaging body has extremely been sent down the volume and has been caused the reliability hidden danger problem, the unbalanced product deformation and the hidden danger of inefficacy that leads to of multiple different material internal stress of full device packaging has been solved, the insufficient problem of the little epoxy packing in the intensive gap of components and parts has been solved. Meanwhile, different packaging schemes of the filter can be selected, and cost control of using a scheme of using a high-cost special film-coated material can be effectively reduced.

The embedded structure of the filter module is provided with a substrate, and a switch chip is embedded in the substrate and positioned between circuits in the substrate; the bottom surface of the substrate is provided with bottom layer circuits arranged at intervals, the intervals between the bottom layer circuits are sealed by substrate ink, and the filter chip is directly or indirectly electrically connected with the front surface of the substrate through a solder ball.

Preferably, the filter packaging body is provided, the filter packaging body consists of a filter chip containing gold columns, a passivation bonding layer, a filter substrate, a resonator and a plastic packaging material, the filter chip is arranged on the filter substrate, the gold columns are connected with the lower end of the filter chip, the gold columns are combined with a gold plating layer on the surface of the filter substrate, the solder balls protrude out of the lower bottom surface of the filter substrate,

the filter chip in the filter package body is indirectly electrically connected with the module substrate through the solder balls, and the filter package body and the substrate are packaged by the module plastic package layer.

More preferably, a cavity is formed between the lower bottom surface of the filter chip and the upper surface of the filter substrate, the resonator is arranged on the lower bottom surface of the filter chip and in the cavity, except the bottom surface, the periphery of the filter chip is coated with a passivation bonding layer, the outer side of the passivation bonding layer is packaged by a plastic packaging material, and the filter substrate and the plastic packaging material are separated by the passivation bonding layer.

Furthermore, the solder balls are arranged at the bottom of the filter packaging body, and the filter chip is directly electrically connected with the front side of the module substrate through the solder balls at the bottom.

In another preferred scheme, the filter chip is coated with a film through a passivation bonding layer and then packaged on the substrate through a module plastic package layer, a cavity is formed between the lower bottom surface of the filter chip and the top surface of the substrate, and the resonator is arranged on the lower bottom surface of the filter chip and in the cavity.

Furthermore, the number of the solder balls is 4-6, and the solder balls are different, according to the functional logic of the filter module, part of the solder balls are connected with the upper end of the switch chip through the bonding pads of the circuit layer of the substrate, and the other part of the solder balls are connected with other functional circuits of the substrate of the module.

Preferably, the device further comprises an inductance passive element arranged inside the substrate.

Preferably, the thickness of the filter chip is 200-.

The invention also provides a manufacturing method of the embedded structure of the filter module, which is characterized by comprising the following steps:

1) designing a substrate:

the substrate is of a four-layer plate structure, the total thickness of the substrate is 300-400 microns, wherein the thickness of ink of the substrate is 25-30 microns, the thickness of a non-chip layer copper column is 30-40 microns, the height of the chip layer copper column is 125-150 microns, the thickness of a circuit layer is 20-25 microns, the width of a substrate circuit is more than 15 microns, the circuit spacing is more than 15 microns, the substrate circuit and the copper column are made of copper materials, organic filling between circuits is semi-curing resin, ABF organic materials are pressed around a chip and an inductance element for filling and curing, the substrate circuit uses a chemical plating process, 0.1-0.3 micron anti-oxidation film OSP is deposited on a front bonding pad after surface treatment of the substrate, nickel-plated palladium gold is plated on the back of the substrate, the thickness of the nickel layer is 3-8 microns, the thickness of the palladium layer is more than 0.1 micron, and the thickness of the gold layer is more than 0.7 micron;

2) manufacturing a substrate:

hair material

The panel is made of an epoxy resin core material doped with glass fiber by using a double-layer circuit superposition method process or a panel which is not provided with the epoxy resin core material doped with glass fiber by using a single-layer circuit incremental method process;

manufacture of inner layer structure of chip and element embedded front substrate

3um base copper decontamination activation, yellow light chamber dry film pressing, non-copper column area dry film exposure, etching unexposed area, electroplating copper column with 200um height, removing exposure dry film, pressing semi-solidified material, baking and solidifying, thinning the semi-solidified material to expose the copper column, wherein the copper column height is about 175um, secondary dry film pasting, exposing non-embedded chip and element area copper column and organic flying area, etching embedded chip and element area dry film, removing exposure dry film, completely removing embedded chip and element area copper column and reserving pasting cavity,

chip and component embedding

Laminating a layer of 5um rear double-sided adhesive film on the surface of a board-level material, adhering the outer surface of the adhesive film on a support plate table steel plate, adhering the inner surface of the adhesive film on the surface of a substrate completely, keeping the adhesive film at a mounting cavity in a viscous state to be suspended above the cavity, removing the substrate support plate when sending materials, exposing the mounting cavity and the bottom section of a copper column and a solidified organic filling area, completing the board rotating process, adhering a 100um chip line and a pad surface in a braid on the adhesive film in a pick & place mode, simultaneously adhering a 100um high ultrathin element conductive position on the adhesive film, completing embedding the chip and the element, laminating a 200um thick non-conductive ABF organic material in a vacuum mode in the cavity adhered with the chip and the element, and ensuring the complete filling; the cavity and the surface of the substrate are in an ABF pressing and completely covering state, the ABF is baked and cured, the ABF is thinned to control the copper column to be exposed and ensure that the chip and the element are not exposed, and the height of the copper column is 125-;

thinning ABF surface copper plating

Thinning the ABF surface copper columns and the cavity ABF, wherein the solidified copper columns are filled with organic materials in a horizontal state, chemically depositing a seed copper layer with the thickness of 3um, and then electroplating the copper layer with the thickness of 30 um;

chip wiring surface and component conductive position fan-out rewiring

Splitting a substrate and a carrier plate of a circuit surface of a chip, tearing off a double-sided adhesive film of the circuit surface of the chip, exposing the surface of the chip, a conductive bonding pad, a conductive position of an element, a copper column of the substrate, ABF and cured and filled organic materials, covering the surface of the chip except 70um bonding pad windowing and other areas with 1-2um insulating protective layers, chemically depositing a copper seed layer with the thickness of 3um, pressing a dry film and exposing a non-circuit area, etching the dry film of the non-circuit area to expose a circuit area, electroplating a circuit layer with the thickness of 20um, removing the dry film of the exposure area and the seed layer of the bottom non-circuit area, pressing semi-cured organic materials, baking and curing,

copper wire circuit forming of substrate with exposed chip back

The turning plate is used for removing dirt and activating a copper layer with the thickness of 30 micrometers exposed on the substrate on the back of the chip, the thickness is reduced to 20 micrometers, a dry film is pressed, exposure is carried out, a dry film in a non-circuit area is etched, the copper with the thickness of 20 micrometers in the non-circuit area is etched, the exposed dry film is removed, a circuit is exposed, semi-cured organic materials are pressed, baking and curing are carried out, the chip and elements are buried in the chip, and the substrate on the front side and the back side of the chip is formed with the circuit;

outer layer circuit forming of substrate

After the front and back surfaces of the substrate are solidified, the organic material is subjected to holing treatment in a laser drilling blind hole mode through alignment confirmation, a circuit pad on an inner layer of the substrate is exposed after laser drilling, a pollution removal and activation pad is formed, a 3-micron seed layer copper material is chemically deposited, and the front and back surfaces of the substrate and a hole disc of a laser hole wall are in a copper material full-coverage state; pressing the dry film to expose the non-circuit area, etching the dry film of the non-exposure area, etching the seed copper material of the non-circuit area, removing the dry film of the exposure area, and electroplating the copper material to increase the thickness of the seed copper with the thickness of 3um to 20um so as to complete front and back hole filling and circuit filling; when a front circuit is designed, the distance between the filter and the filter needs to meet more than 100um, so that effective pasting of an isolation film coated in a later process and effective filling during plastic packaging are ensured;

substrate coated with ink

Coating ink on the front side and the back side of a substrate covering an ink yellow chamber, semi-curing the pre-baking ink, exposing a non-pad windowing area, and exposing pads on the front side and the back side of the substrate in an etching windowing area;

substrate panel splitting single substrate and surface treatment

Punching and splitting a substrate panel into packages, manufacturing the packages into single strips, removing dirt and activating, selecting a surface treatment mode of pads on the front side and the back side of the substrate, plating a nickel-palladium-gold material on the back side of the substrate by using an LGA scheme, wherein the thickness of nickel is 3-8um, the thickness of palladium is 0.1um, the thickness of gold is more than 0.07um, and depositing an OSP (organic solderability preservative) anti-oxidation organic material on the front side of the substrate to finish the surface treatment of the pads of the substrate.

3) Testing, packaging and delivering the substrate;

each unit on the substrate is subjected to circuit testing to sort good products and defective products, the system marks the positions of the defective products, the appearance of the substrate confirms the good products and defective products again, the system records the positions of the defective products again, the laser marks are made on the defective products, the system generates E-mapping, and the packaging and the delivery are carried out to a packaging factory after the number of the good products is counted

4) Module product packaging

5) Test package shipment

Cutting the single piece, forming and checking the appearance, distinguishing good and defective products through appearance checking, performing appearance checking, and performing electrical property testing on the good products after picking out defective products; testing and sorting good products and defective products with different electrical properties, packaging the good products, and outputting the good products and the defective products to an application end after labels are pasted; and analyzing and verifying the defective products, and preparing for improvement of subsequent new products.

Preferably, in the step 4), the module product is packaged secondarily by using a single filter package:

the filter packaging body is mounted according to the frequency band requirement of the design structure, the filter can be of a single-band system or a dual-band system, the dual-band system is any one of B1+ B3, B8+ B26, B2+ B66, B20+ B28, B34+ B39 and B39+ B41,

the filter packaging body structure is that a gold column and a chip are realized on the circuit welding disc surface of a filter chip in an ultrasonic welding mode, the gold column is combined with a filter substrate, the height of the gold column is 10-15 mu m, the chip is reversely buckled on the substrate, a layer of semi-curing agent with the thickness of 20-50 mu m is coated on the chip and the outer surface of the substrate to form a cavity between the circuit surface of the filter and the substrate, the normal work of the cavity structure of a resonator is realized, the semi-curing isolation film is externally subjected to plastic packaging and re-curing to play the standard structure of effective protection of internal elements and surface leveling,

the exposed bonding pads and the module alignment bonding pads on the substrate of the filter package are designed to be circular structures,

the packaging process of the filter module comprises the following steps:

filter packaging body paster

Printing solder paste on a steel screen on the module substrate at the filter pad alignment point, wherein the thickness of the steel screen is 80 um; mounting different filter packages at different positions according to design drawings, performing reflow soldering after the mounting, liquefying and re-solidifying the printing solder paste to realize circuit connection between the terminals of the filter package and the bonding pads of the module substrate, wherein the filter package is supported on the module substrate by cylindrical tin columns on a plurality of terminals, gallery gaps are formed between the tin columns, the vertical distance between the filter package and the module substrate is 40-60 μm,

plastic package of filter module

Epoxy resin plastic package is carried out after the water vapor is removed by reflux baking, the plastic package material selects silicon dioxide or aluminum nitride ceramic balls with the diameter of 20um at the maximum as the filler, the plastic package filling can realize complete and effective filling when the minimum clearance of the plastic package component is more than two times of the diameter of the filler, the plastic package is carried out for 8-12 hours at the constant temperature for baking and curing after the plastic package, the complete crosslinking reaction is ensured,

post-plastic-package process

And (3) carrying out laser marking after baking, marking each element plastic package body of the substrate, and cutting and separating the substrate into single module element finished products for inspection.

In another preferred scheme, the module product packaging process in the step 4) is to use a filter chip with solder balls for packaging:

mounting a filter chip according to the frequency band requirement of the design structure, wherein the filter can be in a single-band mode or a dual-band mode, the dual-band mode is any one of B1+ B3, B8+ B26, B2+ B66, B20+ B28, B34+ B39 and B39+ B41,

preparing a filter chip implanted with solder balls, and performing advanced packaging and solder ball implantation processing by using a 4-inch or 6-inch filter wafer, wherein the thickness of the 4-inch filter wafer is 250 micrometers, the thickness of the 6-inch filter wafer is 350 micrometers, the opening of a chip bonding pad on the filter wafer is 80 micrometers, the diameter of the solder balls after ball implantation is 80 micrometers, and the height of the solder balls is 50 micrometers;

testing the wafer with filter, testing each chip on the wafer with tin ball, generating the distribution diagram of good and defective products,

the packaging process of the filter module comprises the following steps:

filter wafer grinding scribing

The 4-inch wafer does not need to be ground and thinned, the thickness of the 6-inch wafer needs to be thinned to be within 200-plus 250um, the isolation film covering and the overall thickness control of the module in the later process are facilitated, and the single filter chip is in a separated state after scribing.

Filter chip good product braid

Putting the good chips of the filter in the separated state into a braid carrying belt according to the electronic distribution diagram of the good and bad chips, covering, putting each filter chip in one braid in the process, distinguishing different filter chips in different braids, performing label processing,

pasting filter chip

Before mounting, a tin paste printing steel mesh is designed according to a bonding pad of a module substrate corresponding to the filter, all selected filters are mounted after tin paste printing is completed, the process is to mount a plurality of types of filters required in the module at corresponding positions of an embedded element substrate at one time, solder ball reflow soldering is performed after mounting is completed, at the moment, the filter chip is connected with the module substrate through an electrical signal circuit, the distance between the circuit surface of the filter chip and the surface of the module substrate is 20-30 mu m,

coated with an isolation film

Vacuum pasting an isolation film, baking for 2-4 hours in a vacuum oven at a constant temperature of 130 ℃ after pasting the film, ensuring that the isolation film is effectively combined with the filter chip and the module substrate, forming a cavity structure between the circuit surface of each filter chip and the module substrate after the process is finished,

module substrate plastic package

The plastic package of the module substrate is completed on a compression molding plastic package device, the mold-closing pressure of a single-mold-cavity plastic package device is controlled to be 2.3-2.8Ton, the mold-closing pressure of a double-mold-cavity plastic package device is controlled to be 5-6Ton, and the die-closed substrate is baked and cured in a 175 ℃ constant-temperature oven after plastic package.

Post-process machining of filter module

And (4) carrying out laser printing of label characters on the plastic packaging material of each device of the module substrate, and cutting the module substrate to separate each module device for inspection and test.

Preferably, the method further comprises embedding an inductive passive element in the substrate in the step 2).

Preferably, the method further comprises the step 2) of implementing the passive element instead of the inductor in a substrate circuit winding manner in the substrate design stage. The substrate winding is designed according to the matching inductance values at the input and output ends of different filter specifications, and the realization of the inductance function by the substrate winding is described as follows.

A wire inductance conversion formula:

referring to fig. 8, L is an inductance value, L is a substrate trace length, w is a substrate trace width, and h is a substrate trace thickness. Note that the substrate trace inductance is independent of the copper metallization thickness.

From the above formula, if the substrate trace length is reduced by half, the inductance value is also reduced by half. But the width of the trace is increased by 10 times to reduce the inductance by half.

The invention has the following beneficial effects:

the reliability is improved by removing the cavity structure of the switch chip, and the cost is saved by removing the copper column on the switch chip. The built-in switch flip chip without the cavity function in the filter module device saves the copper column reprocessing process, and the bare chip is embedded in the substrate, so that the problems of tin bridging between copper columns and high risk of copper column structure fracture in the flip switch structure are eliminated. The surface of the embedded chip is isolated from the outside to prevent the electrical performance reduction caused by the corrosion of impurities in the air to a chip circuit, protect the surface of the chip, a connecting lead and the like, and prevent the chip from being damaged by external force and influenced by the external environment in the aspects of electrical or thermophysical property and the like.

The thermal expansion coefficient of the chip is matched with that of the substrate by completely filling the epoxy resin in the substrate, so that the stress generated by the change of external environments such as heat and the like and the internal stress generated by the heating of the chip are effectively relieved, and the chip can be prevented from being damaged or the copper columns and the solder balls are prevented from being broken and losing efficacy. Meanwhile, the installation and the transportation are convenient.

The filling is complete and effective, firm and reliable mechanical support can be provided for the chip 1 and other components, the device can adapt to the change of various working environments and conditions, the accumulated heat is dissipated when the device works for a long time, the normal work of the system in the range of the requirement of the use temperature is ensured, and the device is convenient for packaging users, circuit board manufacturers and semiconductor manufacturers and is convenient for standardization

This scheme changes the encapsulation of full device in the wave filter module into partial encapsulation and buries in partial base plate, the conflict problem of filter cavity tectorial membrane and flip-chip switch chip copper post space fully filled has been solved, the problem of the interpolar space filling of inductance passive component has been solved, the filter packaging body has been solved and has been caused reliable hidden danger problem by minimizing the volume, it leads to product deformation and inefficacy hidden danger to have solved the unbalance of multiple different material internal stress of full device encapsulation, the insufficient problem of the little epoxy packing in the intensive gap of components and parts has been solved. Meanwhile, different packaging schemes of the filter can be selected, and cost control of the scheme of using the high-cost special film-coated material can be effectively reduced.

Structurally, the scheme is effectively strengthened by module design and structural building.

First, the inductive device is optimized. The method comprises the steps of placing the inductance passive element in the substrate, and coating and protecting the inductance passive element by using an ABF organic material. And in the second method, the functions of the inductance passive element are realized in a substrate winding mode through early-stage design electrical simulation and laboratory matching debugging, and the inductance passive element is removed. The filter package body PiP package and the filter chip package can be protected by any selective structure.

Secondly, the flip switch chip is embedded in the substrate instead. The switch chip is arranged inside the substrate and is coated and protected by ABF organic materials. The radio frequency module substrate is embedded into a switch chip structure for protection, the space of a filter paster is not limited, and the area of the module on a terminal PCB can be reduced in a customized mode.

Thirdly, single-side packaging of the single filter. The first method is to mount the filter package on the front surface of the substrate through soldering tin, and effectively fill and protect the gap between the filter package and the substrate with epoxy resin. In the second method, the filter chip with the implanted solder balls is attached to the front side of the substrate, the isolation film is attached, and then the epoxy resin is effectively filled. The strengthening mode can not only play a role in physical protection, but also reduce the use cost of materials.

Drawings

Fig. 1 is a schematic structural diagram of a filter module according to embodiment 1 of the present invention;

fig. 2 is a schematic structural diagram of a filter package;

FIG. 3 is a schematic structural diagram of a filter module according to embodiment 2 of the present invention;

FIG. 4 is a schematic diagram of a filter chip according to the present invention;

FIG. 5 is a schematic diagram of a switch chip;

fig. 6 and 7 are schematic structural diagrams of a conventional product;

FIG. 8 is a schematic diagram of inductance, substrate trace length, and substrate trace width.

Detailed Description

The following describes in more detail embodiments of the present invention with reference to the schematic drawings. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is provided solely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

Referring to fig. 1, a filter module according to embodiment 1 of the present invention includes a substrate 6, a front surface of the substrate 6 is a PiP structure, a plurality of packaged filter packages 1 are attached to the front surface of the substrate 6 and are packaged by a module plastic package layer 2, and a switch chip 8 and an inductor passive element 10 are disposed inside the substrate. The filter packages 1 are separate and not directly connected to each other. The substrate 6 is a four-layer structure, as shown in fig. 1 and fig. 2, the total thickness of the substrate is 300-.

The structure of the filter package 1 is shown in fig. 2 and fig. 4, and is composed of a filter chip 1-1 containing gold posts 1-4, a passivation bonding layer 1-3, a filter substrate 1-5, resonators 1-2, and plastic package materials 1-7. The filter chip 1-1 is arranged on the filter substrate 1-5, the gold posts 1-4 are connected with the lower end of the filter chip 1-1, the gold posts 1-4 are inserted into the filter substrate 1-5, the lower ends of the gold posts 1-4 are provided with solder balls 1-6, and the solder balls 1-6 protrude out of the lower bottom surface of the filter substrate 1-5. A cavity 1-8 is arranged between the lower bottom surface of the filter chip 1-1 and the upper side surface of the filter substrate 1-5, and the resonator 1-2 is arranged on the lower bottom surface of the filter chip 1-1 and in the cavity 1-8. Except the bottom surface, the periphery of the filter chip 1-1 is coated with a passivation bonding layer 1-3, and the outer side of the passivation bonding layer 1-3 is packaged by a plastic package material 1-7. The filter substrate 1-5 and the plastic package material 1-7 are separated by a passivation bonding layer 1-3. The thickness of the filter chip is 200-250um, the thickness of the passivation bonding layer is 1-3 20-50um, the filter substrate 1-5 is formed by overlapping two or more layers of circuits, the thickness is 110-200um, the interconnection layer of the filter chip 1-1 and the filter substrate 1-5 is mainly 10-15um gold posts 1-4, and the total thickness of the filter packaging body 1 is 450-550 um.

The outermost edge from the filter chip 1-1 to the plastic package material 1-7 needs to be larger than 50um, and is better than 75um or more, the larger the distance is, the stronger the reliability of preventing water absorption is, and the embodiment is 80 um.

With continued reference to FIG. 1, the bottom surface of the substrate 6 is provided with spaced bottom traces 6-4, the spaces between the bottom traces 6-4 are sealed by the substrate ink 6-1, and thus the bottom traces 6-4 and the substrate ink 6-1 are spaced at the bottom of the substrate 6.

Referring to fig. 3, a filter module according to an embodiment of the present invention 2 is shown, in which a substrate 6 is the same as that of embodiment 1, and a filter chip 1-1 is coated with a passivation adhesive layer 1-3 and then encapsulated on the substrate by a module plastic encapsulation layer 2. A cavity 1-8 is arranged between the lower bottom surface of the filter chip 1-1 and the top surface of the filter substrate 6, and the resonator 1-2 is arranged on the lower bottom surface of the filter chip 1-1 and in the cavity 1-8. Except the bottom surface, the periphery of the filter chip 1-1 is coated with a passivation bonding layer 1-3, and the outer side of the passivation bonding layer 1-3 is packaged by a module plastic packaging layer 2. The substrate 6 is internally provided with a plurality of layers of circuits, including three layers of circuits 6-5, a bottom layer of circuits 6-4 and two layers of circuits 6-7, and the switch chip 8 is arranged among the plurality of layers of circuits.

The manufacturing method of the filter module of the invention comprises the following steps:

1. preparing materials:

the switch chip 8:

the method uses the switch chip without the copper column in reasonable cost control and area effectiveness, the pad window of the functional opening of the switch chip is 70um, the pad distance is 130um, and the copper column is combined with the pad of the functional opening of the chip through the substrate. The wafer is firstly subjected to electrical property test to screen out chips reaching the standard, the thickness is thinned to 100um from 750um, the chips are cut into single crystal grain switch chips, and the switch chips with the electrical property reaching the standard are packaged to be ready for being buried into a substrate. As shown in FIG. 5, the upper end of the switch chip bonding pad is connected with a copper column 8-1, and the upper end of the copper column 8-1 is provided with a tin cap 8-2.

Substrate 6:

the substrate 6 is a four-layer structure, as shown in fig. 1-fig. 3, the total thickness of the substrate is 300-400um, wherein the thickness of the ink of the substrate is 25-30um, the thickness of the copper pillar of the non-chip layer is 30-40um, the height of the copper pillar of the chip layer is 125-150um, the thickness of the circuit layer is 20-25um, the width of the circuit of the substrate is more than 15um, and the distance between the circuits is more than 15 um.

Substrate material: the substrate circuit and the copper column are made of copper materials, organic filling between the circuits is semi-cured resin, and ABF organic materials are pressed around the chip and the inductance element to fill and fix the circuit, so that the problems of deformation, circuit breaking and the like caused by internal stress can be effectively prevented.

3. The substrate manufacturing process comprises the following steps: the substrate circuit uses a chemical plating process, an external-pulling electroplating wire is not needed, and the product area is effectively utilized. The anti-oxidation film OSP is deposited on a bonding pad on the front surface of the substrate surface treatment, the back surface of the substrate is bonded with nickel-palladium-gold plating, the thickness of the nickel layer is 3-8um, the thickness of the palladium layer is more than 0.1um, and the thickness of the gold layer is more than 0.7 um.

Arranging the panels: the substrate panel arrangement and the substrate material object information imprinting content are designed, so that the material mixing in the processing process is avoided, and the production management and traceability are realized.

3.1, sending materials:

the epoxy resin core material doped with the glass fiber by using the double-layer circuit superposition method process can also be used as a panel without the epoxy resin core material doped with the glass fiber by using the single-layer circuit incremental method process. The embodiment of the invention selects a single-layer line increasing method process material as a process manufacturing instruction.

3.2 chip and element embedding front substrate inner layer structure preparation:

the method comprises the following steps of 3 um-based copper decontamination and activation, dry film pressing in a yellow light room, dry film exposure of a non-copper cylinder region, etching of an unexposed region, electroplating of a 200 um-height copper cylinder, removing the exposure dry film, pressing of a semi-solidified material, baking and curing, thinning of the semi-solidified material to expose the copper cylinder, and enabling the height of the copper cylinder to be about 175 um. And (4) pasting a dry film for the second time, exposing the non-embedded chip and element region copper column and the organic fly forming region, etching the embedded chip and element region dry film, and removing the exposed dry film. At this time, the copper columns of the embedded chip and the element region are completely removed and a mounting cavity is reserved.

3.3 chip and component embedding:

and pressing a layer of 5um back double-sided adhesive film on the surface of the plate-level material, wherein the outer surface of the adhesive film is bonded on the steel plate of the support plate platform, the inner surface of the adhesive film is completely bonded on the surface of the substrate, and the adhesive film at the mounting cavity is kept above the viscous suspension cavity. And (4) removing the substrate carrier plate during material distribution, and exposing the bottom sections of the mounting cavity and the copper column and the solidified organic filling area to finish the plate rotating process. And (3) sticking the chip circuit with the thickness of 100um and the bonding pad surface in the braid on the adhesive film in a pick & place form, and sticking the conductive position of the ultrathin element with the height of 100um on the adhesive film to complete the embedding of the chip and the element. And pressing a non-conductive ABF organic material with the thickness of 200um in a vacuum mode in the cavity attached with the chip and the element to ensure complete filling. At this point, both the cavity interior and the substrate surface will be in an ABF press fit and fully covered state. Baking the fixed telephone ABF, thinning the ABF to control the exposure of the copper column and ensure that the chip and the element are not exposed, wherein the height of the copper column is about 125-150 mu m.

3.4 thinning ABF surface copper plating

Thinning the ABF surface copper columns, forming cavities ABF, filling solidified copper columns in a horizontal state, performing chemical deposition on seed copper layers with the thickness of 3um, and then performing electroplating on the copper layers to reach the thickness of 30 um.

3.5 chip routing side and component conductive sites fan out rewiring.

And splitting the substrate and the carrier plate of the circuit surface of the chip, tearing off the double-sided adhesive film of the circuit surface of the chip, exposing the surface of the chip, the conductive bonding pad, the conductive position of the element, the copper column of the substrate, ABF and the cured and filled organic material. At this time, the chip surface except 70um pad window is covered by 1-2um insulation protective layer. Chemical deposition 3um thickness copper seed layer, pressure dry film and the non-circuit region of exposure, the regional dry film of etching non-circuit exposes the circuit district, electroplates 20um thickness circuit layer, goes to expose regional seed layer 3um copper material of regional dry film of region and the bottom non-circuit, and pressfitting semi-solid organic material bakes the solidification.

3.6 the back of the chip is exposed out of the substrate copper wire circuit for molding.

The board turns over exposes 30um thickness copper layer scrubbing activation to chip back base plate, and thickness attenuate to 20um presses the dry film, and the exposure etches the regional dry film of non-circuit, and the regional 20um thick copper of non-circuit of etching removes the exposure dry film, exposes the circuit. And pressing the semi-cured organic material, and baking and curing. At this time, the chip and the element are embedded, and the front and back substrates of the chip are formed with circuits.

And 3.7, forming the outer layer circuit of the substrate.

The design of the module substrate is relatively complex, a circuit layer needs to be added to 4 layers or more to support full signal and performance layout, and particularly, the inductance element is realized in a mode of winding a coil on the substrate circuit and the purpose of reducing cost, and the inductance element needs to be added on an outer layer circuit. The specific implementation mode is as follows: organic material behind the positive back solidification of base plate confirms through counterpointing to handle organic material trompil with laser drill blind hole form, exposes base plate inlayer circuit pad behind the laser drilling, and the scrubbing activates the pad, and chemical deposition 3um seed layer copper product, and positive back of base plate and laser hole wall hole dish are in the copper product state of covering entirely this moment. And (3) pressing a dry film to expose a non-circuit area, etching a dry film of the non-exposure area, etching a seed copper material of the non-circuit area, removing the dry film of the exposure area, electroplating the copper material to increase the thickness of the seed copper with the thickness of 3um to 20um, and completing front and back hole filling and circuit. Compared with the scheme in the industry, the front outer layer circuit of the substrate in the process has more enough space, and the substrate can be designed and processed according to different schemes of mounting a filter packaging body or a filter flip chip in a post-packaging process. When the front line is designed, the distance between the filter and the filter needs to meet more than 100um, so that the effective pasting of the isolation film coated in the later process and the effective filling during plastic packaging are ensured.

3.8 the substrate is inked.

And coating ink on the front side and the back side of the substrate covering the ink yellow chamber, semi-curing the pre-baking ink, exposing a non-pad windowing area, and etching the windowing area to expose pads on the front side and the back side of the substrate.

3.9 substrate panel the individual substrates and the surface treatment are split.

Stamping the substrate panel apart into packages can produce a single bar size. The method comprises the steps of decontamination and activation, and selection of a pad surface treatment mode on the front and back sides of a substrate, wherein the LGA scheme is adopted, nickel-palladium-gold plating materials are plated on the back side of the substrate in a pad mode, the thickness of nickel is 3-8 mu m, the thickness of palladium is 0.1 mu m, the thickness of gold is more than 0.07 mu m, and OSP anti-oxidation organic materials are deposited on the front side of the substrate to finish the pad surface treatment of the substrate.

And 4, testing the substrate, packaging and shipping. Each unit on the substrate is used for conducting circuit testing and sorting non-defective products, and the system marks the positions of the non-defective products. The appearance of the substrate confirms the good product and the defective product again, and the system records the position of the defective product again. And (4) laser marking defective products of the objects, generating E-mapping by a system, counting the number of the good products, and packaging and delivering the good products to a packaging factory.

And 5, packaging the module product. As described in 3.7, the filter module package may be packaged secondarily by using a 100% yield filter package unit that has been packaged and tested, or may be packaged by flip chip with a filter chip containing tin balls. The filter packaging body can be of a 4G single-frequency band receiving end system type or a 4G double-frequency band receiving end system type. The frequency bands 1, 2, 3, 5, 7, 8, 20, 26, 28, 34, 39, 40, 41 and 66 are selected for use according to different terminal platforms. The processing and manufacturing method of the two schemes comprises the following steps:

5.1 secondary packaging with a single filter package.

The filter package is mounted according to the frequency band requirement of the design structure, the filter can be a single-band system or a dual-band system, and the common dual-band system mainly comprises combinations of B1+ B3, B8+ B26, B2+ B66, B20+ B28, B34+ B39, B39+ B41 and the like. The cost of fabrication and material usage of the dual-band filter integration scheme is relatively ideal and would increase space-saving as a preferred solution.

The filter packaging body structure is characterized in that a gold column and a chip are realized on a circuit welding disc surface of a filter chip in an ultrasonic welding mode, the gold column is combined with a filter substrate, the height of the gold column is 10-15 micrometers, the chip is reversely buckled on the substrate, a layer of semi-solidified film with the thickness of 20-50 micrometers is covered on the chip and the outer surface of the substrate to form a cavity between the circuit surface of the filter and the substrate, normal work of a resonator cavity structure is realized, plastic packaging and re-solidification are carried out outside the semi-solidified isolating film, and a standard structure for effective protection of internal elements and surface leveling is realized.

The exposed bonding pad and the module alignment bonding pad on the substrate of the filter packaging body are designed to be of a circular structure, the plastic packaging process is favorable for epoxy resin plastic packaging material vortex filling in module secondary packaging, and the phenomenon that the gap between the substrate of the filter and the substrate of the module is filled with the plastic packaging material to cause different terminal tin material bridging short circuits is prevented.

And (5) a filter module packaging process.

5.1.1 Filter Package Patch.

Printing solder paste on a steel screen on the module substrate at the filter pad alignment point, wherein the thickness of the steel screen is 80 um; and mounting different filter packaging bodies at different positions according to the design drawing, wherein the process is completed by mounting at one time. Reflow soldering is carried out after mounting, printed solder paste is liquefied and then solidified to realize that the terminals of the filter packaging body are in circuit connection with the bonding pads of the module substrate, at the moment, the filter packaging body is supported on the module substrate through cylindrical tin columns on a plurality of terminals, gallery gaps are formed among the tin columns, the vertical distance between the filter packaging body and the module substrate is 40-60um, and the gaps are the minimum gaps in the packaging process.

And 5.1.2 plastic packaging the filter module.

Epoxy resin plastic package is carried out after water vapor is removed through backflow baking, silicon dioxide or aluminum nitride ceramic balls with the diameter of 20um at the maximum are selected as fillers for plastic package materials, and the plastic package filling can be completely and effectively carried out when the minimum gap of a plastic package component is larger than two times of the diameter of the fillers, so that the flowability of the plastic package materials in the plastic package process is guaranteed, and the gap position filling and supporting effects can be achieved. The packaging process is a thermosetting epoxy resin micromolecule crosslinking reaction process, and constant-temperature baking and curing are carried out for 8-12 hours at 175 ℃ after plastic packaging, so that the crosslinking reaction is completely ensured.

And 5.1.3, processing after plastic packaging.

And (4) carrying out laser marking after baking, and marking each element plastic package body of the substrate. Cutting and separating the substrate into single module component products. And (5) performing appearance inspection, and performing electrical property test on the good product after picking out the defective product.

5.2 use the filter chip package with solder ball.

The filter chip is mounted according to the frequency band requirement of the design structure, the filter can be in a single-frequency-band system or a dual-frequency-band system, and the common dual-frequency-band system mainly comprises combinations of B1+ B3, B8+ B26, B2+ B66, B20+ B28, B34+ B39, B39+ B41 and the like. The cost of fabrication and material usage of the dual-band filter integration scheme is relatively ideal and would increase space-saving as a preferred solution.

Preparing a filter chip with solder balls. The advanced packaging tin ball implantation processing is carried out by using 4-inch or 6-inch filter chips, the thickness of the 4-inch filter chips is 250um, the thickness of the 6-inch filter chips is 350um, the chip bonding pad opening on the filter chips is 80um, the diameter of the tin ball is 80um after the ball implantation, and the height of the tin ball is 50 um.

And (4) measuring in the filter chip. And testing each chip on the wafer with the tin ball implanted, and generating an electronic distribution diagram of good products and defective products in the system.

And (5) a filter module packaging process.

And 5.2.1 grinding and scribing the filter chip.

4 cun wafers need not grind the attenuate, and 6 cun wafers need attenuate thickness to within 200 and one or more 250um, make things convenient for the later process barrier film to cover and the whole thickness control of module. And the single filter chip is in a separated state after scribing.

5.2.2 good filter chip braid.

And placing the good filter chips in the separation state on the braid carrying belt and covering the good filter chips according to the good and bad filter electronic distribution diagram, placing each filter chip in one braid in the process, distinguishing different filter chips in different braids, and performing label processing.

And 5.2.3 mounting a filter chip.

Before mounting, a solder paste steel mesh is printed according to a pad of a module substrate corresponding to the filter, all selected filters are mounted after solder paste printing is completed, the filters of multiple types needed in the module are mounted at the corresponding positions of the embedded element substrate in one step in the process, and solder ball reflow soldering is performed after mounting is completed. At the moment, the filter chip is connected with the module substrate through an electrical signal circuit, and the distance between the circuit surface of the filter chip and the surface of the module substrate is 20-30 mu m.

And 5.2.4 covering the isolating film.

And (3) coating an isolation film in vacuum, baking for 2-4 hours in a vacuum oven at a constant temperature of 130 ℃ after film coating, and ensuring that the isolation film is effectively combined with the filter chip and the module substrate. After the process is finished, a cavity structure is formed between the circuit surface of each filter chip and the module substrate, and the normal work of the resonators between the circuits of the filter chips can be guaranteed.

And 5.2.5 carrying out plastic package on the module substrate.

The plastic package of the module substrate is completed on a compression molding plastic package device, the mold closing pressure of the single-mold-cavity plastic package device is controlled to be 2.3-2.8Ton, and the mold closing pressure of the double-mold-cavity plastic package device is controlled to be 5-6Ton, so that the mold closing pressure is effectively controlled by the device to ensure that an isolation film is not broken by the plastic package material under high pressure. After plastic packaging, baking in a constant temperature oven at 175 ℃ and curing.

5.2.6 post-processing of the filter module.

And (4) carrying out laser printing on label characters on the plastic packaging material of each device of the module substrate, and cutting the module substrate to separate each module device. And (5) distinguishing good and defective products by appearance inspection. And (5) performing appearance inspection, and performing electrical property test on the good product after picking out the defective product.

And 6, testing, packaging and shipping. And testing and sorting the good products and the defective products with different electrical properties, packaging the good products, sticking labels and delivering the products to an application end. And analyzing and verifying the defective products, and preparing for improvement of subsequent new products.

The foregoing detailed description of the preferred embodiments is intended to more clearly illustrate the features and spirit of the present invention, and not to limit the scope of the invention by the preferred embodiments disclosed above. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

Claims (13)

1. An embedded structure of a filter module comprises a substrate (6), and is characterized in that a switch chip (8) is embedded between circuits in the substrate; the bottom surface of the substrate is provided with bottom layer circuits arranged at intervals, the intervals between the bottom layer circuits are sealed by substrate ink, and the filter chip (1-1) is directly or indirectly electrically connected with the front surface of the substrate through a solder ball (1-6).

2. The embedded structure of filter module set according to claim 1, wherein there is a filter package (1) composed of a filter chip (1-1) having gold posts (1-4) thereon, a passivation adhesive layer (1-3), a filter substrate (1-5), resonators (1-2), and a plastic sealing material (1-7), the filter chip is disposed on the filter substrate, the gold posts are connected to the lower end of the filter chip, the gold posts are bonded to the surface of the filter substrate with gold plating, the solder balls (1-6) protrude from the lower bottom surface of the filter substrate (1-5),

the filter chip in the filter packaging body is indirectly electrically connected with the module substrate through the solder balls, and the filter packaging body and the substrate are packaged by a module plastic packaging layer (2).

3. The embedded structure of a filter module according to claim 2, wherein the cavity (1-8) is formed between the lower bottom surface of the filter chip and the upper surface of the filter substrate, the resonator is disposed on the lower bottom surface of the filter chip and in the cavity, the periphery of the filter chip except the bottom surface is covered with a passivation adhesive layer, the outer side of the passivation adhesive layer is encapsulated with a plastic package material, and the filter substrate and the plastic package material are separated by the passivation adhesive layer.

4. The embedded structure of filter module as defined in claim 1, wherein solder balls (1-6) are provided on the bottom of the filter package, and the filter chip is directly electrically connected to the front surface of the module substrate through the bottom solder balls.

5. The embedded structure of a filter module according to claim 4, wherein the filter chip is encapsulated on the substrate by a module molding layer after being coated with a passivation adhesive layer (1-3), the filter chip having a cavity (1-8) between a bottom surface thereof and a top surface thereof, the resonator being disposed on the bottom surface of the filter chip and in the cavity.

6. The embedded structure of filter module set of claim 5, wherein there are 4-6 solder balls with different numbers, and according to the functional logic of filter module set, part of the solder balls are connected to the upper end of the switch chip (8) through the bonding pads of the circuit layer of the substrate, and the other part of the solder balls are connected to other functional circuits of the substrate of the module set.

7. Embedded structure of filter modules according to claim 3 or 6, characterized by further comprising an inductive passive element (10) placed inside the substrate.

8. The embedded structure of the filter module as claimed in claim 3, wherein the thickness of the filter chip is 200-.

9. A manufacturing method of a buried structure of a filter module is characterized by comprising the following steps:

1) designing a substrate:

the substrate is of a four-layer plate structure, the total thickness of the substrate is 300-400 microns, wherein the thickness of ink of the substrate is 25-30 microns, the thickness of a non-chip layer copper column is 30-40 microns, the height of the chip layer copper column is 125-150 microns, the thickness of a circuit layer is 20-25 microns, the width of a substrate circuit is more than 15 microns, the circuit spacing is more than 15 microns, the substrate circuit and the copper column are made of copper materials, organic filling between circuits is semi-curing resin, ABF organic materials are pressed around a chip and an inductance element for filling and curing, the substrate circuit uses a chemical plating process, 0.1-0.3 micron anti-oxidation film OSP is deposited on a front bonding pad after surface treatment of the substrate, nickel-plated palladium gold is plated on the back of the substrate, the thickness of the nickel layer is 3-8 microns, the thickness of the palladium layer is more than 0.1 micron, and the thickness of the gold layer is more than 0.7 micron;

2) manufacturing a substrate:

hair material

The panel is made of an epoxy resin core material doped with glass fiber by using a double-layer circuit superposition method process or a panel which is not provided with the epoxy resin core material doped with glass fiber by using a single-layer circuit incremental method process;

manufacture of inner layer structure of chip and element embedded front substrate

3um base copper decontamination activation, yellow light chamber dry film pressing, non-copper column area dry film exposure, etching unexposed area, electroplating copper column with height of 200um, removing exposure dry film, pressing semi-solidified material, baking and solidifying, thinning the semi-solidified material to expose the copper column, wherein the height of the copper column is about 175um, secondary dry film pasting, exposing non-embedded chip and element area copper column and organic flying area, etching the embedded chip and element area dry film, removing the exposure dry film, completely removing the embedded chip and element area copper column and reserving a pasting cavity,

chip and component embedding

Laminating a layer of 5-micron rear double-sided adhesive film on the surface of a board-level material, adhering the outer surface of the adhesive film on a steel plate of a carrier plate table, completely adhering the inner surface of the adhesive film on the surface of a substrate, keeping the adhesive film at a mounting cavity in a viscous state and suspending above the cavity, removing the substrate carrier plate during material sending, exposing the cross sections of the mounting cavity and a copper column bottom layer and a cured organic filling area, completing the board rotating process, adhering a 100-micron chip circuit and a bonding pad surface in a braid on the viscous adhesive film in a pick & place mode, simultaneously adhering a 100-micron high ultrathin element conductive position on the viscous adhesive film, completing a chip and an element, and laminating a 200-micron non-conductive ABF organic material in a vacuum mode in the cavity adhered with the chip and the element to ensure complete filling; the cavity and the surface of the substrate are in an ABF pressing and completely covering state, the ABF is baked and cured, the ABF is thinned to control the copper column to be exposed and ensure that the chip and the element are not exposed, and the height of the copper column is 125-;

thinning ABF surface copper plating

Thinning the ABF surface copper columns and the cavity ABF, wherein the solidified copper columns are filled with organic materials in a horizontal state, chemically depositing a seed copper layer with the thickness of 3um, and then electroplating the copper layer with the thickness of 30 um;

chip wiring surface and component conductive position fan-out rewiring

Splitting a substrate and a carrier plate of a circuit surface of a chip, tearing off a double-sided adhesive film of the circuit surface of the chip, exposing the surface of the chip, a conductive bonding pad, a conductive position of an element, a copper column of the substrate, ABF and cured and filled organic materials, covering the surface of the chip except 70um bonding pad windowing and other areas with 1-2um insulating protective layers, chemically depositing a copper seed layer with the thickness of 3um, pressing a dry film and exposing a non-circuit area, etching the dry film of the non-circuit area to expose a circuit area, electroplating a circuit layer with the thickness of 20um, removing the dry film of an exposure area and 3um copper materials of the seed layer of the bottom non-circuit area, pressing semi-solidified organic materials and baking and solidifying,

copper wire circuit forming of substrate with exposed chip back

The turning plate exposes a copper layer with the thickness of 30um on the back of the chip for decontamination and activation, the thickness is thinned to 20um, a dry film is pressed, exposure is carried out, a dry film in a non-circuit area is etched, the copper with the thickness of 20um in the non-circuit area is etched, the dry film is exposed, a circuit is exposed, a semi-cured organic material is pressed and baked and cured, the chip and the element are embedded, and the circuit molding is completed on the substrate on the front side and the back side of the chip;

outer layer circuit forming of substrate

After the front and back surfaces of the substrate are solidified, the organic material is subjected to holing treatment in a laser drilling blind hole mode through alignment confirmation, a circuit pad on an inner layer of the substrate is exposed after laser drilling, a pollution removal and activation pad is formed, a 3-micron seed layer copper material is chemically deposited, and the front and back surfaces of the substrate and a hole disc of a laser hole wall are in a copper material full-coverage state; pressing a dry film to expose a non-circuit area, etching a dry film of the non-exposure area, etching a seed copper material of the non-circuit area, removing the dry film of the exposure area, electroplating the copper material to increase the thickness of the seed copper with the thickness of 3um to 20um, and completing front and back hole filling and circuit filling; when a front circuit is designed, the distance between the filter and the filter needs to meet more than 100um, so that effective pasting of an isolation film coated in a later process and effective filling during plastic packaging are ensured;

substrate coated with ink

Coating ink on the front side and the back side of a substrate covering an ink yellow chamber, semi-curing the pre-baking ink, exposing a non-pad windowing area, and exposing pads on the front side and the back side of the substrate in an etching windowing area;

substrate panel splitting single substrate and surface treatment

Punching and splitting the substrate panel into packages, manufacturing the packages into single strips, removing dirt and activating, selecting a surface treatment mode of a pad on the front side and the back side of the substrate, plating a nickel-palladium-gold material on the back side of the substrate by using an LGA scheme, wherein the thickness of nickel is 3-8 mu m, the thickness of palladium is 0.1 mu m, the thickness of gold is more than 0.07 mu m, and depositing an OSP anti-oxidation organic material on the front side of the substrate to finish the surface treatment of the pad of the substrate.

3) Testing, packaging and delivering the substrate;

each unit on the substrate is subjected to circuit testing to sort good products and defective products, the system marks the positions of the defective products, the appearance of the substrate confirms the good products and defective products again, the system records the positions of the defective products again, the laser marks are made on the defective products, the system generates E-mapping, and the packaging and the delivery are carried out to a packaging factory after the number of the good products is counted

4) Module product packaging

5) Test package shipment

Cutting the single piece, forming and checking the appearance, distinguishing good and defective products through appearance checking, performing appearance checking, and performing electrical property testing on the good products after the defective products are picked out; testing and sorting good products and defective products with different electrical properties, packaging the good products, sticking labels and delivering the products to an application end; and analyzing and verifying the defective products, and preparing for improvement of subsequent new products.

10. The method as claimed in claim 9, wherein the step 4) module product packaging process is a secondary packaging process using a single filter package:

the filter packaging body is mounted according to the frequency band requirement of the design structure, the filter can be in a single-frequency-band mode or a dual-frequency-band mode, the dual-frequency-band mode is any one of B1+ B3, B8+ B26, B2+ B66, B20+ B28, B34+ B39 and B39+ B41,

the filter packaging body structure is that a gold column and a chip are realized on the circuit welding disc surface of a filter chip in an ultrasonic welding mode, the gold column is combined with a filter substrate, the height of the gold column is 10-15 mu m, the chip is reversely buckled on the substrate, a layer of semi-curing agent with the thickness of 20-50 mu m is coated on the chip and the outer surface of the substrate to form a cavity between the circuit surface of the filter and the substrate, the normal work of the cavity structure of a resonator is realized, the semi-curing isolation film is externally subjected to plastic packaging and re-curing to play the standard structure of effective protection and surface leveling of internal elements,

the exposed bonding pads and the module alignment bonding pads on the substrate of the filter package are designed to be circular structures,

the packaging process of the filter module comprises the following steps:

filter packaging body paster

Printing solder paste on a steel screen on the module substrate at the filter pad alignment point, wherein the thickness of the steel screen is 80 um; mounting different filter packages at different positions according to design drawing, performing reflow soldering after mounting, liquefying and re-solidifying the printed solder paste to realize the circuit connection of the terminals of the filter package and the bonding pads of the module substrate, wherein the filter package is supported on the module substrate by cylindrical tin columns on a plurality of terminals, gallery gaps are formed among the tin columns, the vertical distance between the filter package and the module substrate is 40-60um,

plastic package of filter module

Performing reflux baking to remove water vapor, performing epoxy resin plastic package, selecting silica dioxide or aluminum nitride ceramic ball with diameter of 20um at maximum as filler for plastic package material, performing plastic package filling when minimum gap of plastic package component is larger than twice of filler diameter to realize complete and effective filling, performing constant temperature baking and curing at 175 ℃ for 8-12 hours after plastic package to ensure complete crosslinking reaction,

post-plastic-package process

And (3) carrying out laser marking after baking, marking each element plastic package body of the substrate, and cutting and separating the substrate into single module element finished products for inspection.

11. The method as claimed in claim 9, wherein the step 4) module product packaging process is a solder ball-containing filter chip packaging process:

mounting a filter chip according to the frequency band requirement of the design structure, wherein the filter can be in a single-band mode or a dual-band mode, the dual-band mode is any one of B1+ B3, B8+ B26, B2+ B66, B20+ B28, B34+ B39 and B39+ B41,

preparing a filter chip implanted with solder balls, and performing advanced packaging and solder ball implantation processing by using a 4-inch or 6-inch filter wafer, wherein the thickness of the 4-inch filter wafer is 250 micrometers, the thickness of the 6-inch filter wafer is 350 micrometers, the opening of a chip bonding pad on the filter wafer is 80 micrometers, the diameter of the solder balls after ball implantation is 80 micrometers, and the height of the solder balls is 50 micrometers;

testing the wafer with filter, testing each chip on the wafer with tin ball, generating the distribution diagram of good and defective products,

the packaging process of the filter module comprises the following steps:

filter wafer grinding scribing

The 4-inch wafer does not need to be ground and thinned, the thickness of the 6-inch wafer needs to be thinned to be within 200-plus 250um, the isolation film covering and the overall thickness control of the module in the later process are facilitated, and the single filter chip is in a separated state after scribing.

Filter chip good product braid

Putting the good chips of the filter in the separated state into a braid carrying belt and covering the good chips and the bad chips according to an electronic distribution diagram of the good chips and the bad chips, putting each filter chip into one braid in the process, distinguishing different filter chips into different braids, and performing label processing,

pasting filter chip

Before mounting, a tin paste printing steel mesh is designed according to a bonding pad of a module substrate corresponding to the filter, all selected filters are mounted after tin paste printing is completed, the process is to mount a plurality of types of filters required in the module at corresponding positions of the embedded element substrate in one time, solder ball reflow soldering is performed after mounting is completed, at the moment, the filter chip is connected with the module substrate through an electrical signal circuit, the distance between the circuit surface of the filter chip and the surface of the module substrate is 20-30 mu m,

coated with an isolation film

Vacuum pasting an isolation film, baking for 2-4 hours in a vacuum oven at a constant temperature of 130 ℃ after pasting the film to ensure that the isolation film is effectively combined with the filter chip and the module substrate, forming a cavity structure between the circuit surface of each filter chip and the module substrate after the process is finished,

module substrate plastic package

The plastic package of the module substrate is completed on a compression molding plastic package device, the mold clamping pressure of a single-mold-cavity plastic package device is controlled to be 2.3-2.8Ton, the mold clamping pressure of a double-mold-cavity plastic package device is controlled to be 5-6Ton, and the die is baked and cured in a constant-temperature oven at 175 ℃ after plastic package.

Post-process machining of filter module

And (4) carrying out laser printing of label characters on the plastic packaging material of each device of the module substrate, and cutting the module substrate to separate each module device for inspection and test.

12. The method as claimed in any one of claims 9 to 11, further comprising embedding an inductive passive element in the substrate in step 2).

13. The method as claimed in any one of claims 9 to 11, further comprising implementing the substrate design stage in step 2) in a substrate line looping manner to replace the inductive passive component.

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