CN111586965B

CN111586965B - LCP substrate-based high-power conformal component preparation method and conformal component

Info

Publication number: CN111586965B
Application number: CN202010452075.9A
Authority: CN
Inventors: 罗燕; 刘凯; 丁蕾; 张�诚; 陈桂莲; 王立春
Original assignee: Shanghai Spaceflight Electronic and Communication Equipment Research Institute
Current assignee: Shanghai Spaceflight Electronic and Communication Equipment Research Institute
Priority date: 2020-05-25
Filing date: 2020-05-25
Publication date: 2022-03-22
Anticipated expiration: 2040-05-25
Also published as: CN111586965A

Abstract

The invention provides a preparation method of a high-power conformal component based on LCP (liquid Crystal Polymer) base materials and the conformal component, which comprises an LCP multilayer board, a chip and a shell, wherein the LCP multilayer board is arranged on the shell; the shell is provided with a boss, and the LCP multilayer board is provided with a chip embedding groove matched with the boss; the LCP multilayer board is sleeved on the LCP multilayer board through the chip embedding groove; the chip is arranged on the end face of the boss and is electrically connected with the metal layer on the upper side face of the LCP multi-layer board through a bonding lead. According to the invention, the LCP substrate with good high-frequency stability and low loss is used for preparing the component substrate, so that the signal loss can be effectively reduced, the problems that the common radio frequency substrate is low in application frequency and cannot be conformally assembled are solved, compared with the flexible substrate, the problem that the flexible substrate is poor in heat dissipation and cannot be applied to mounting a high-power chip is solved, and the integrated heat dissipation packaging of a conformal component and a shell is realized.

Description

LCP substrate-based high-power conformal component preparation method and conformal component

Technical Field

The invention relates to the technical field of electronic packaging, in particular to a high-power conformal component preparation method based on LCP (liquid crystal display) substrates and a conformal component.

Background

In the manufacturing industry, the conformal technology refers to arranging circuits according to device structures to realize the integration of structural circuits. This technique can greatly reduce the volume of the assembly, especially the volume of a complex assembly. Conformal technology will become the primary means for miniaturization of electronic components, leading to the trend of future electronic component manufacturing. With the development of miniaturization of the components, the integrated circuit and structure needs to be processed and manufactured.

Liquid Crystal Polymers (LCP) are particularly useful for high frequency printed circuit boards due to their outstanding dielectric properties, good dimensional stability, excellent low moisture absorption and electrical insulation. And due to the flexible characteristic of LCP, the LCP can be perfectly conformal with the curved surface shell, the integrated packaging of the high-frequency assembly can be realized, and the miniaturized and light curved surface high-frequency assembly is obtained. However, the organic substrate has poor heat dissipation performance and high junction temperature of the power chip, so that the risk of burning loss exists, and the structural function integration, miniaturization and curved surface of the assembly can be realized through the integrated packaging of the LCP substrate and the aluminum-silicon shell.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a preparation method of a high-power conformal component based on LCP (liquid crystal display) base materials, which aims to solve the problems that the existing rigid radio-frequency substrate is not conformal, the flexible radio-frequency substrate has poor heat dissipation performance to a power chip, poor high-frequency performance and the like.

According to the invention, the preparation method of the LCP substrate-based high-power conformal component comprises the following steps:

step S1: etching transmission line patterns on two side faces of a first LCP substrate layer, a second LCP substrate layer and a third LCP substrate layer in the multilayer LCP circuit board, and plating metal layers on the transmission line patterns to form metallization wiring;

step S2: a second layer connecting layer is pasted between two opposite side surfaces of the second layer LCP substrate and the third layer LCP substrate, and is sequentially pre-cured and laminated, then through holes penetrating through the second layer LCP substrate, the third layer LCP substrate, the second layer connecting layer and metal layers on the second layer LCP substrate, the third layer LCP substrate and the second layer connecting layer along the thickness direction are punched, and then the through holes are metalized;

step S3: processing metal bumps corresponding to the through holes on the first LCP substrate, processing connecting layer holes on the first connecting layer and corresponding to the metal bumps, pre-curing the first connecting layer on the lower surface of the second LCP substrate, and laminating the metal bumps by penetrating the connecting layer holes;

step S4: punching grounding holes penetrating through the first LCP substrate, the first connecting layer, the second LCP substrate, the second connecting layer and the third LCP substrate along the thickness direction, and metalizing the grounding holes so as to electrically connect the lower side surface of the first LCP substrate with the metal layer on the upper side surface of the third LCP substrate;

step S5: a passive device is pasted on the metal layer on the upper side surface of the third LCP substrate;

step S6: processing a chip embedding groove penetrating through the first LCP substrate layer, the second LCP substrate layer and the third connecting layer in the thickness direction;

step S7: bending the multilayer LCP circuit board to a preset radian;

step S8: and sleeving the multilayer LCP circuit board on a boss of the shell through a chip embedding groove, attaching the chip on the boss, and electrically connecting the chip and the metal layer of the third LCP substrate through a bonding lead.

Preferably, in step S1, each LCP substrate in the multi-layer LCP circuit board adopts a double-sided copper-clad LCP substrate;

the metal layer is a Ni layer, a Pd layer and an Au layer which are sequentially overlapped on the upper side face of the third LCP substrate.

Preferably, in the step S2, during the pre-curing, specifically, when the second layer connection layer is attached to the lower surface of the third layer LCP substrate, the second layer connection layer and the third layer LCP substrate are pre-cured by heating on a heat table at 130-150 ℃ for 30S.

Preferably, in the step S2 and the step S3, during lamination, specifically, lamination is performed in vacuum, wherein the lamination temperature is 180-220 ℃, and the pressure is 300 psi.

Preferably, in step S4, when the grounding hole is metalized, a Pd seed layer is sputtered upward from the lower side of the first-layer LCP substrate facing the grounding hole, and then Cu, Ni, and Au layers are sequentially electroless-plated.

Preferably, the size of the chip embedding slot matches with the boss of the housing.

Preferably, after the multi-layer LCP circuit board is bent to the preset radian in the step S7, annealing is carried out at 80-100 ℃ for 0.5-1 h.

Preferably, the multilayer LCP substrate is bonded to the housing by epoxy conductive glue and cured at 100 ℃ for 1h in step S8.

The high-power conformal component is prepared by the preparation method of the high-power conformal component based on the LCP substrate, and comprises an LCP multilayer board, a chip and a shell;

the shell is provided with a boss, and the LCP multilayer board is provided with a chip embedding groove matched with the boss; the LCP multilayer board is sleeved on the shell through the chip embedding groove;

the chip is arranged on the end face of the boss and is electrically connected with the metal layer on the upper side face of the LCP multi-layer board through a bonding lead.

Preferably, the LCP multilayer board comprises a first layer of LCP substrate, a second layer of LCP substrate, and a third layer of LCP substrate; two side surfaces of the first LCP substrate, the second LCP substrate and the third LCP substrate are provided with transmission line patterns, and the transmission line patterns are plated with metal layers;

a first connecting layer is arranged between two opposite side surfaces of the first LCP substrate and the second LCP substrate; a second layer connecting layer is arranged between two opposite side surfaces of the second layer LCP substrate and the third layer LCP substrate;

through holes penetrating through metal layers on the second layer LCP substrate, the third layer LCP substrate, the second layer connecting layer and the second layer LCP substrate, the third layer LCP substrate and the second layer connecting layer are formed on the second layer LCP substrate, the third layer LCP substrate and the second layer connecting layer, and the through holes are metalized through holes;

the first LCP substrate is provided with metal bumps corresponding to the through holes, the first connecting layer is provided with connecting layer holes corresponding to the metal bumps, and the metal bumps penetrate through the connecting layer holes and are electrically connected with the through holes;

a passive device is pasted on the metal layer on the upper side surface of the third LCP substrate;

first layer LCP base plate, first layer articulamentum second layer LCP base plate, second layer articulamentum and it has along the thickness direction to open on the third layer LCP base plate runs through first layer LCP base plate, first layer articulamentum second layer LCP base plate, second layer articulamentum and the ground connection hole of third layer LCP base plate is right the ground connection hole is metallized, with the electricity connection first layer LCP base plate downside with the metal level of side on the third layer LCP base plate.

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

according to the invention, the LCP substrate with good high-frequency stability and low loss is used for preparing the component substrate, so that the signal loss can be effectively reduced, the problems that the common radio frequency substrate is low in application frequency and cannot be conformally assembled are solved, compared with the flexible substrate, the problem that the flexible substrate is poor in heat dissipation and cannot be applied to mounting a high-power chip is solved, and the integrated heat dissipation packaging of a conformal component and a shell is realized.

The preparation method realizes the preparation of the conformal curved surface component by integrally packaging the LCP substrate and the aluminum-silicon shell, and can be applied to conformal platforms.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic diagram of a high power conformal device according to an embodiment of the present invention;

fig. 2 is a flow chart of steps of a method of fabricating a high power conformal component based on LCP substrates in an embodiment of the invention;

FIG. 3 is a schematic illustration of a lithographic pattern for a single layer substrate according to an embodiment of the present invention;

FIG. 4 is a schematic illustration of a partial substrate lamination in an embodiment of the present invention;

FIG. 5 is a schematic illustration of blind via formation lamination in an embodiment of the present invention;

FIG. 6 is a schematic illustration of ground hole metallization in an embodiment of the present invention;

FIG. 7 is a schematic diagram of passive device mounting in an embodiment of the invention;

FIG. 8 is a schematic illustration of laser machining of a chip embedded trench in an embodiment of the present invention;

FIG. 9 is a schematic illustration of a curved pre-form of a multi-layer substrate according to an embodiment of the present invention;

FIG. 10 is a schematic view of the assembly of a substrate and a housing in an embodiment of the invention;

fig. 11 is a schematic diagram of die attach bonding according to an embodiment of the invention.

In the figure: 101-a housing; 102-a first layer LCP substrate; 103-a first layer of tie layer; 104-a second layer LCP substrate; 105-a second layer connection layer; 106-a third LCP substrate; 107-metallization wiring; 108-passive devices; 109-chip; 110-bonding wires; 111-ground via; 112-blind holes; 113-a via; 114-metal bumps; 115-tie layer holes; 116-chip embedding slot.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

Fig. 1 is a schematic structural diagram of a high-power conformal component according to an embodiment of the present invention, and as shown in fig. 1, the high-power conformal component provided by the present invention is prepared by the LCP substrate-based high-power conformal component preparation method, and includes an LCP multilayer board, a chip 109, and a housing 101;

the shell 101 is provided with a boss, and the LCP multilayer board is provided with a chip embedding groove 116 matched with the boss; the LCP multilayer board is sleeved on the housing 101 through the chip embedding groove 116;

the chip 109 is disposed on the end face of the boss and is electrically connected to the metal layer on the upper side of the LCP multilayer board by bonding wires 110.

In an embodiment of the present invention, the LCP multi-layer board includes a first layer LCP substrate 102, a second layer LCP substrate 104, and a third layer LCP substrate 106; two side surfaces of the first layer LCP substrate 102, the second layer LCP substrate 104 and the third layer LCP substrate 106 are provided with transmission line patterns, and the transmission line patterns are plated with metal layers;

a first layer of connecting layer 103 is arranged between two opposite sides of the first layer of LCP substrate 102 and the second layer of LCP substrate 104; a second layer connecting layer 105 is arranged between two opposite sides of the second layer LCP substrate 104 and the third layer LCP substrate 106;

through holes 113 penetrating through metal layers on the second-layer LCP substrate 104, the third-layer LCP substrate 106, the second-layer LCP substrate 105, the third-layer LCP substrate 106 and the second-layer LCP substrate 105 are formed on the second-layer LCP substrate 104, the third-layer LCP substrate 106 and the second-layer LCP substrate 105, and the through holes 113 are metalized through holes;

a metal bump 114 corresponding to the position of the through hole 113 is formed on the first LCP substrate 102, a connection layer hole 115 is formed on the first connection layer 103 corresponding to the position of the metal bump 114, and the metal bump 114 passes through the connection layer hole 115 and is electrically connected to the through hole 113;

a passive device is attached to the metal layer on the upper side of the third LCP substrate 106;

the first layer LCP substrate 102, the first layer connecting layer 103, the second layer LCP substrate 104, the second layer connecting layer 105 and the third layer LCP substrate 106 are provided with a grounding hole 111 penetrating through the first layer LCP substrate 102, the first layer connecting layer 103, the second layer LCP substrate 104, the second layer connecting layer 105 and the third layer LCP substrate 106 along the thickness direction, and the grounding hole 111 is metallized so as to electrically connect the lower side surface of the first layer LCP substrate 102 and the metal layer on the upper side surface of the third layer LCP substrate 106.

Fig. 2 is a flowchart illustrating steps of a method for manufacturing a high-power conformal device based on an LCP substrate according to an embodiment of the present invention, and as shown in fig. 2, the method for manufacturing a high-power conformal device based on an LCP substrate according to the present invention includes the following steps:

step S1: etching transmission line patterns on two sides of a first layer LCP substrate 102, a second layer LCP substrate 104 and a third layer LCP substrate 106 in the multi-layer LCP circuit board, and plating metal layers on the transmission line patterns to form metallized wirings 107;

step S2: a second layer connecting layer 105 is pasted between two opposite side surfaces of the second layer LCP substrate 104 and the third layer LCP substrate 106, and is sequentially pre-cured and laminated, then through holes 113 penetrating through the second layer LCP substrate 104, the third layer LCP substrate 106, the second layer connecting layer 105 and metal layers on the second layer LCP substrate 104, the third layer LCP substrate 106 and the second layer connecting layer 105 along the thickness direction are punched, and then the through holes 113 are metalized;

step S3: processing a metal bump 114 corresponding to the position of the through hole 113 on the first-layer LCP substrate 102, processing a connecting layer hole 115 corresponding to the position of the metal bump 114 on the first-layer connecting layer 103, pre-curing the first-layer connecting layer 103 on the lower surface of the second-layer LCP substrate 104, and then laminating the metal bump 114 through the connecting layer hole 115;

step S4: punching a grounding hole 111 penetrating through the first layer of LCP substrate 102, the first layer of connecting layer 103, the second layer of LCP substrate 104, the second layer of connecting layer 105 and the third layer of LCP substrate 106 along the thickness direction, and metalizing the grounding hole 111 to electrically connect the metal layers on the lower side of the first layer of LCP substrate 102 and the upper side of the third layer of LCP substrate 106;

step S5: mounting a passive device on the metal layer on the upper side of the third LCP substrate 106;

step S6: machining a chip embedding groove 116 penetrating through the first layer LCP substrate 102, the second layer LCP substrate 104 and the third layer connecting layer in the thickness direction;

step S7: bending the multilayer LCP circuit board to a preset radian;

step S8: the multilayer LCP circuit board is sleeved on the boss of the housing 101 through the chip embedding groove 116, the chip 109 is attached on the boss, and the chip 109 and the metal layer of the third LCP substrate 106 are electrically connected through the bonding wire 110.

FIG. 3 is a schematic diagram of the photolithography pattern of the single-layer substrate in the embodiment of the present invention, as shown in FIG. 3, in step S1, each LCP substrate in the multi-layer LCP circuit board is a double-sided copper-clad LCP substrate;

the metal layer is a Ni layer, a Pd layer, and an Au layer that are sequentially overlapped on the upper side of the third LCP substrate 106.

In an embodiment of the invention, the first, second and

third LCP substrates

102, 104, 106 are 100 μm thick, double-sided copper clad. The LCP substrate can be cut into a round shape according to the size of a laminating tool, and the LCP substrate is cleaned by a chemical method to remove oil stains and impurities on the surface.

The metal layer is used for wire bonding of the chip 109.

In the embodiment of the present invention, the metallization line 107 may be formed by plating a metal layer on a copper layer, or may be formed by etching the copper layer, sputtering the metal layer by sputtering, and then thickening by electroplating.

Fig. 4 is a schematic view illustrating partial substrate lamination in the embodiment of the present invention, as shown in fig. 4, when the pre-curing is performed in step S2, specifically, when the second layer connecting layer 105 is attached to the lower surface of the third layer LCP substrate 106, the second layer connecting layer 105 and the third layer LCP substrate 106 are pre-cured by heating on a heat stage at 130 to 150 ℃ for 30S.

In the embodiment of the present invention, the third LCP substrate 106, the second connecting layer 105 and the second LCP substrate 104 are laminated in vacuum at 180-220 deg.C under a pressure of 300 psi.

FIG. 5 is a schematic diagram of blind via formation lamination in an embodiment of the present invention, as shown in FIG. 5, during lamination in step S2 and step S3, specifically, lamination is performed in vacuum at a lamination temperature of 180-220 ℃ and a pressure of 300 psi.

In the embodiment of the present invention, metal bumps 114 are processed on the substrate at the blind holes 112 of the first-layer LCP substrate 102 by a wire-bonding ball bonding machine, the first-layer connecting layer 103 is processed with connecting layer holes 115 at the corresponding positions of the blind holes 112, the first-layer connecting layer 103 is pre-cured on the lower surface of the second-layer LCP substrate 104, and then the metal bumps 114 are laminated in vacuum through the connecting layer holes 115.

In the embodiment of the present invention, the metal bump 114 is a copper bump. The blind hole 112 is metallized by a through hole 113 and is formed by plugging a metal layer.

Fig. 6 is a schematic diagram of ground via metallization according to an embodiment of the present invention, and as shown in fig. 6, in step S4, when the ground via 111 is metalized, a Pd seed layer is sputtered upward from the lower side of the first LCP substrate 102 facing the ground via 111 to prevent the Pd from covering the circuit pattern, and then Cu, Ni, and Au are sequentially electroless plated.

In the embodiment of the present invention, the grounding hole 111 is formed by laser.

Fig. 7 is a schematic diagram of mounting a passive device according to an embodiment of the present invention, and as shown in fig. 7, in the embodiment of the present invention, a passive device 108 is mounted by using a conductive epoxy glue.

In the embodiment of the invention, the passive device can be prepared by a thin film process, can be embedded by referring to a chip embedding method, and can be surface-mounted, and the specific method is considered according to the circuit design layout.

Fig. 8 is a schematic diagram of laser processing of a chip embedding groove in an embodiment of the present invention, and as shown in fig. 8, the size of the chip embedding groove 116 matches with the boss of the housing 101.

In the embodiment of the present invention, the chip burying groove 116 of the multi-layer board is processed by means of laser processing. The laser used was an all-solid-state uv laser with a laser wavelength of 355 nm.

Fig. 9 is a schematic diagram of a pre-bending of a multi-layer substrate according to an embodiment of the present invention, as shown in fig. 9, after the multi-layer LCP circuit board is bent to a preset arc in step S7, it is annealed at 80-100 ℃ for 0.5-1 h.

In the embodiment of the invention, the LCP multilayer substrate is bent by a preset radian by adopting a tool.

Fig. 10 is a schematic illustration of the assembly of the substrate and the housing in an embodiment of the present invention, as shown in fig. 10, the layer LCP substrate is bonded on the housing 101 by epoxy conductive glue and cured at 100 ℃ for 1h in step S8.

Fig. 11 is a schematic diagram of die attach wire bonding according to an embodiment of the present invention, and as shown in fig. 11, a die 109 is attached to a bump of a housing 101 and interconnected with a metal layer on a substrate through a bonding wire 110.

In the embodiment of the present invention, the material of the housing 101 is a high silicon aluminum alloy, the CTE of the material is similar to the CTE of the GaAs chip 109, and the material has good heat dissipation performance and can also be molybdenum copper.

The cushion block material for mounting the chip 109 is a Cu, Mo and Cu composite material, the CTE of the material is similar to that of the GaAs chip 109, the heat dissipation performance is good, and the cushion block is selected according to the material of the chip 109 and can also be molybdenum copper, molybdenum and the like.

In the embodiment of the invention, LCP materials with low cost, low dielectric constant and low moisture absorption rate are selected as the substrate and the airtight material of the component, the preparation of the component is realized by combining methods such as electroplating, laser processing and the like, the chip embedding is carried out through the chip embedding groove, the heat dissipation of the chip is carried out through the shell, the integration level of the component is improved, and the conformation of the component and the curved surface platform is realized.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.

Claims

1. A method for preparing a high power conformal component based on an LCP substrate, comprising the steps of:

step S7: bending the multilayer LCP circuit board to a preset radian;

2. The LCP substrate-based high power conformal component preparation method according to claim 1, wherein in step S1, each LCP substrate in the multi-layer LCP circuit board adopts a double-sided copper-clad LCP substrate;

3. The method for preparing the LCP substrate-based high-power conformal component of claim 1, wherein the pre-curing in step S2 is performed by heating the third LCP substrate and the second LCP substrate on a heat stage at 130-150 ℃ for 30S.

4. The method for preparing a high power conformal component based on LCP substrate as claimed in claim 1, wherein the lamination is performed in step S2 and step S3, specifically, in vacuum, the lamination temperature is 180-220 ℃, and the pressure is 300 psi.

5. The LCP substrate-based high power conformal component preparation method according to claim 1, wherein in step S4, when the grounding hole is metallized, a Pd seed layer is sputtered from the lower side of the first layer LCP substrate facing the grounding hole upwards, and then Cu, Ni and Au layers are electroless plated in sequence.

6. The LCP substrate-based high power conformal component preparation method according to claim 1, wherein the size of the chip embedding groove matches with the boss of the housing.

7. The LCP substrate-based high power conformal component preparation method according to claim 1, wherein the multi-layer LCP circuit board is annealed at 80-100 ℃ for 0.5-1 h after being bent to a preset arc in step S7.

8. The LCP substrate-based high power conformal component preparation method according to claim 1, wherein the multi-layer LCP substrate is bonded on the shell by epoxy conductive glue and cured at 100 ℃ for 1h in step S8.

9. A high power conformal component prepared by the LCP substrate-based high power conformal component preparation method of any one of claims 1 to 8, comprising an LCP multilayer board, a chip and a shell;

10. The high power conformal assembly of claim 9, wherein the LCP multi-layer board comprises a first layer LCP substrate, a second layer LCP substrate, and a third layer LCP substrate; two side surfaces of the first LCP substrate, the second LCP substrate and the third LCP substrate are provided with transmission line patterns, and the transmission line patterns are plated with metal layers;