Fully conformal ultrathin integrated phased-array antenna and manufacturing process method thereof

Abstract

The invention belongs to the technical field of phased-array antennas, and particularly relates to a fully conformal ultrathin integrated phased-array antenna and a manufacturing process method thereof. The manufacturing process method comprises the following steps of: planarizing an expandable curved surface, and manufacturing a positioning hole, a conducting hole, a heat dissipation hole, a circuit pattern and a cavity on a green tape according to a circuit design drawing; a special high-precision curved surface alignment lamination tool is used for loading a half-green ceramic tape; sequentially placing a PET (Polyethylene Terephthalate) film and a silica gel film on the raw ceramic tape for coating, carrying out vacuum encapsulation by adopting a transparent plastic encapsulation tape, and then carrying out warm water lamination operation; sintering the green tape by adopting a curved quartz glass sintering bracket, and pressing the green tape by adopting a quartz pressing block during sintering; the curved surface gasket is adhered to the bottom of the groove of the green tape by using a conductive adhesive, and then the chip is adhered to the curved surface gasket. According to the fully conformal ultrathin integrated phased-array antenna and the manufacturing process method thereof, integrated design is achieved, and cracking, wrinkling and layering occurring after the substrate is curved are avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of phased array antennas, and particularly relates to a fully conformal ultra-thin integrated phased array antenna and a manufacturing process method thereof. Background Art

[0002] Most modern aircraft are required to have the performance of stealth, long range, and long loiter time. In order to achieve the stealth performance, the antenna needs to meet the requirement of conformal with the carrier aircraft. In order to achieve the combat performance of long range and long loiter time, the antenna needs to meet the requirements of high integration, thinness, and miniaturization. In the fifth-generation electronic packaging technology, multilayer LTCC is an important technical approach for developing microwave integrated components, multi-chip modules (MCM), and system-in-package (SiP) due to its characteristics such as high-density wiring, high signal transmission speed, low loss, good plasticity, and processability, and has received great attention at home and abroad.

[0003] At present, LTCC substrate technology is mainly used to realize the integration of planar antenna radiation surface arrays, power distribution networks, TR components, etc., in order to achieve the lightweight and miniaturization of the antenna, but no breakthrough has been made in the conformal of the antenna array surface, and the commonly used conformal scheme is the radome conformal. The reason is that the existing LTCC substrate technology is difficult to realize the curved surface conformal design and manufacturing of the RF antenna front end, specifically manifested in: 1. The design of the curved surface conformal antenna is difficult, including the full conformal integration of the antenna radiation surface, power distribution network, TR components, etc., and the power amplifier output end needs to be connected by a vertical interconnection structure between multiple curved surfaces; 2. It is difficult to achieve precise curved surface forming and pattern conversion for multilayer curved surface LTCC, and it is difficult to ensure the high-precision alignment of the interlayer through holes during the green ceramic lamination; 3. The curved surface LTCC will crack, wrinkle, and delaminate during the green ceramic curved surface forming stage and the shape-preserving sintering stage.

[0004] In the reports of foreign literature, a two-step lamination method is proposed to realize the design and manufacturing of the ultra-thin integrated phased array antenna framework. First, the planar antenna is manufactured according to the conventional LTCC process and laminated, and then the shape-preserving secondary lamination is carried out using a curved surface forming tooling. This causes the convex green ceramic layer to be stretched and the concave green ceramic to be compressed, forming large stresses, which are prone to cause warping and cracking of the curved surface antenna during sintering. This method depends on the tensile properties of the material and can only be used for cases with very small curvature and very large curvature radius. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the purpose of the present invention is to provide a new design and a manufacturing process method that can not only ensure the integrated design of the fully conformal ultra-thin phased array antenna but also solve the problems of cracking, wrinkling, and delamination that occur after the substrate is curved.

[0006] The technical solution adopted by the present invention is as follows:

[0007] Manufacturing process method for a fully conformal ultra-thin integrated phased array antenna, comprising the following steps:

[0008] S1: After planarizing the deployable surface, make positioning holes, via holes, heat dissipation holes, circuit patterns and cavities on the green tape according to the circuit design pattern;

[0009] S2: High-precision lamination stage of green tape: Use a special high-precision curved surface alignment and lamination tooling to clamp the green tape;

[0010] S3: Curved surface forming stage of green tape: Place a PET film and a silicone film on the laminated green tape in sequence, perform vacuum encapsulation with a transparent plastic encapsulation tape, and then carry out warm water lamination operation;

[0011] S4: Conformal sintering stage: Sinter the green tape with a curved surface quartz glass sintering bracket, and use a quartz pressing block to press the green tape during sintering;

[0012] S5: Perform chip mounting: First, use conductive adhesive to bond the curved surface gasket to the bottom of the groove of the green tape to realize the conversion of the chip mounting bottom from a curved surface to a plane, and then bond the chip to the curved surface gasket.

[0013] The present invention first converts the curved surface to a plane to adjust the positions of the through holes in each layer, then uses a film-free process to first demold the green ceramic sheet, and after aging treatment, performs subsequent processes. It uses a high-precision alignment and lamination tooling for lamination, and then performs conformal single-layer lamination and conformal sintering. The curved surface conformal LTCC manufacturing method can be applied to a large range of curvature radii. Operating according to this can complete the design and manufacturing of a fully conformal ultra-thin integrated phased array antenna framework that meets the requirements.

[0014] As a preferred solution of the present invention, in step S1, during the conversion process from a curved surface to a planarization, it is necessary to consider the influence of the green tape thickness on the position fitting of the positioning holes, via holes, and heat dissipation holes in different layers, and establish a correction compensation model.

[0015] As a preferred solution of the present invention, in step S1, when making the positioning holes, via holes, and heat dissipation holes, when the hole diameter is 1 mm, the error in the X direction and the Y direction is within ±1 μm; the positioning holes, via holes, and heat dissipation holes in each layer are replaced by round holes, and the surface pattern size error is ±15 μm.

[0016] As a preferred solution of the present invention, in step S2, when clamping the green tape, pin positioning is used.

[0017] As a preferred solution of the present invention, in step S3, during the warm water lamination operation, the conformal lamination preheating temperature is 70 °C, the time is 60 min, and the lamination pressure is 262 Kgf / cm 2 , and the pressure is maintained for 10 min.

[0018] As a preferred embodiment of the present invention, in step S4, when the sintering temperature is below 450°C, the heating rate ≤ 5°C / s; when the sintering temperature is in the range of 450°C to 850°C, the heating rate is controlled at 5°C / s to 8°C / s.

[0019] As a preferred embodiment of the present invention, in step S4, when using a quartz pressing block to press the green ceramic tape, the pressure is 10 - 20 Kgf / cm 2 .

[0020] The fully conformal ultra-thin integrated phased array antenna includes a base. A curved cavity is provided on one side of the base. A multi-layer LTCC curved substrate is provided in the curved cavity. An antenna array is provided on the side of the multi-layer LTCC curved substrate away from the base; several chips are connected to the side of the multi-layer LTCC curved substrate facing the base. Several antenna RF interfaces are provided on the antenna array. Several vias are provided in the multi-layer LTCC curved substrate, and wires connecting the chips and the antenna RF interfaces are provided in the vias.

[0021] As a preferred embodiment of the present invention, several grooves are provided on the side of the multi-layer LTCC curved substrate facing the base. The grooves communicate with the vias, and the chips are mounted in the grooves.

[0022] As a preferred embodiment of the present invention, a RF main port and a connector are also provided on the side of the multi-layer LTCC curved substrate facing the base.

[0023] The beneficial effects of the present invention are as follows:

[0024] The present invention first converts the curved surface to a plane to adjust the positions of the through holes in each layer, then uses a film-free process to first demold the green ceramic sheet, and after aging treatment, performs subsequent processes. It uses a high-precision alignment and laminating tooling for lamination, and then performs conformal first lamination and conformal sintering. The method for manufacturing the curved surface conformal LTCC can be applied to a relatively large range of curvature radii. Operating according to this can complete the design and manufacture of the fully conformal ultra-thin integrated phased array antenna framework that meets the requirements. Description of the Drawings

[0025] Figure 1 is a schematic diagram of the design of the curved surface conformal antenna framework;

[0026] Figure 2 is the front view and right view of the curved surface conformal antenna;

[0027] Figure 3 is a schematic diagram of the high-precision curved surface alignment and laminating tooling;

[0028] Figure 4 is a schematic diagram of using a curved surface quartz glass sintering bracket for conformal sintering;

[0029] Figure 5 is a schematic diagram of the recommended sintering curve of the present invention;

[0030] Figure 6 It is a schematic diagram of chip mounting.

[0031] In the figure: 1 - base; 2 - multi - layer LTCC curved substrate; 3 - antenna array; 4 - chip; 5 - antenna RF interface; 6 - high - precision curved surface alignment and lamination tooling; 7 - curved surface quartz glass sintering bracket; 8 - quartz pressing block; 9 - curved surface gasket; 21 - via hole; 22 - groove; 23 - RF main port; 24 - connector; 25 - green tape. Specific embodiments

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0034] As Figures 1 to 6 shown, the manufacturing process method of the fully conformal ultra - thin integrated phased array antenna includes the following steps:

[0035] 1) As Figure 1 and Figure 2 shown, the fully conformal ultra - thin integrated phased array antenna framework integrates the antenna array 3, complex feeding network, vertical interconnection interface, multi - layer LTCC substrate, etc.

[0036] 2) The conformal antenna is a deployable curved surface. After planarizing the deployable curved surface, positioning holes, via holes 21, heat dissipation holes, circuit patterns, cavities, etc. are made on the green tape 25 according to the circuit design pattern. The conversion process needs to consider the influence of the thickness of the green tape 25 on the fitting of the positions of vias in different layers, and a correction compensation model is established. When the aperture is 1 mm, the errors in the X - direction and Y - direction are within ±1 μm, the vias in each layer are replaced by round holes, and the error of the surface pattern size is ±15 μm.

[0037] 3) As Figure 3As shown in the figure, in the stage of high-precision lamination of green ceramics, a special high-precision curved surface alignment and lamination tooling 6 is used, which is made of high-quality carbon structural steel 45. The tooling has the same curvature as the green body, the radius of curvature ≤ 350 mm, and the positioning accuracy of the tooling is ±20 μm. Pin positioning is adopted, the positioning accuracy of the pin is ±10um, the concentricity is ±10 μm, and the alignment accuracy between the curved surface LTCC layers is ±80 μm.

[0038] 4) In the stage of forming the curved surface of green ceramics, a PET film with a thickness of 50um and a silica gel film with a thickness of 1mm are sequentially placed on the LTCC green body after lamination, and then vacuum encapsulation is carried out with a transparent plastic encapsulation tape, and then warm water lamination operation is carried out. The preheating temperature of the shape-preserving lamination is 70 °C, the time is 60 min, and the lamination pressure is 262 Kgf / cm 2 , and the pressure is maintained for 10 min.

[0039] 5) As Figure 4 and Figure 5 shown in the figure, in the stage of shape-preserving sintering, a curved surface quartz glass sintering bracket 7 is used. The curvature of this tooling is the same as that of the green body, and the surface roughness is 3.2 - 6.4. When the sintering temperature is below 450 °C, the heating rate ≤ 5 °C / s; when the sintering temperature is in the range of 450 °C - 850 °C, the heating rate is controlled at 5 °C / s - 8 °C / s. During the shape-preserving sintering process, a quartz pressing block 8 is needed to press the green body to avoid the green body bending due to thermal expansion and contraction, and the pressure is 10 - 20 Kgf / cm 2 .

[0040] 6) As Figure 6 shown in the figure, finally, the curved surface LTCC chip 4 is mounted. First, the curved surface gasket 9 is bonded to the bottom of the cavity with conductive adhesive, and the curvature is the same as the installation position, realizing the conversion of the bottom of the chip 4 installation from a curved surface to a plane, and then the chip 4 is bonded to the curved surface gasket 9.

[0041] The present invention first converts the curved surface to a plane to adjust the positions of the through holes in each layer, then uses a film-free process to first demold the green ceramic sheet, and after aging treatment, subsequent processes are carried out. A high-precision alignment and lamination tooling is used for lamination, and then shape-preserving single-layer lamination and shape-preserving sintering are carried out. The method for manufacturing curved surface conformal LTCC can be applied to a large range of curvature radii. According to this operation, the design and manufacture of a fully conformal ultra-thin integrated phased array antenna framework that meets the requirements can be completed.

[0042] As Figure 1 and Figure 2As shown in the figure, the assembly structure of the fully conformal ultra-thin integrated phased array antenna prepared by the present invention includes a base 1. A curved cavity is provided on one side of the base 1. A multi-layer LTCC curved substrate 2 is provided in the curved cavity. An antenna array 3 is provided on the side of the multi-layer LTCC curved substrate 2 away from the base 1. A number of chips 4 are connected to the side of the multi-layer LTCC curved substrate 2 facing the base 1. A number of antenna RF interfaces 5 are provided on the antenna array 3. A number of via holes 21 are provided in the multi-layer LTCC curved substrate 2. Wires connecting the chips 4 and the antenna RF interfaces 5 are respectively provided in the via holes 21. A number of grooves 22 are provided on the side of the multi-layer LTCC curved substrate 2 facing the base 1. The grooves 22 communicate with the via holes 21. The chips 4 are mounted in the grooves 22. A RF total port 23 and a connector 24 are further provided on the side of the multi-layer LTCC curved substrate 2 facing the base 1.

[0043] The present invention is not limited to the above optional embodiments. Any person can obtain other various forms of products under the inspiration of the present invention. However, no matter what changes are made in its shape or structure, as long as the technical solutions fall within the scope defined by the claims of the present invention, they all fall within the protection scope of the present invention.

Claims

1. A manufacturing process method for a fully conformal ultra-thin integrated phased array antenna, characterized in that: It includes the following steps: S1: After planarizing the deployable surface, make positioning holes, via holes (21), heat dissipation holes, circuit patterns, and cavities on the green tape (25) according to the circuit design pattern; S2: High-precision lamination stage of green ceramic: Clamp the green tape (25) using a special high-precision curved surface alignment and lamination tooling (6); S3: Curved surface forming stage of green tape (25): Place a PET film and a silica gel film on the laminated green tape (25) in sequence, perform vacuum encapsulation using a transparent plastic encapsulation tape, and then carry out warm water lamination operation; S4: Shape-preserving sintering stage: Sinter the green tape (25) using a curved surface quartz glass sintering bracket (7), and press the green tape (25) with a quartz pressing block (8) during sintering; after sintering, obtain a multi-layer LTCC curved surface substrate (2); S5: Perform chip (4) mounting: First, use conductive adhesive to bond the curved surface gasket (9) to the bottom of the groove (22) of the multi-layer LTCC curved surface substrate (2) to realize the conversion of the chip (4) mounting bottom from a curved surface to a plane, and then bond the chip (4) to the curved surface gasket (9).

2. The manufacturing process method of the fully conformal ultra-thin integrated phased array antenna according to claim 1, wherein: In step S1, during the conversion process from a curved surface to a planarization, the influence of the thickness of the green tape (25) on the position fitting of positioning holes, via holes (21), and heat dissipation holes in different layers needs to be considered, and a correction compensation model is established.

3. The manufacturing process method of the fully conformal ultra-thin integrated phased array antenna according to claim 1, characterized in that: In step S1, when making positioning holes, via holes (21), and heat dissipation holes, when the hole diameter is 1 mm, the errors in the X direction and Y direction are within ±1 μm; the positioning holes, via holes (21), and heat dissipation holes in each layer are replaced by round holes, and the surface pattern size error is ±15 μm.

4. The manufacturing process method of the fully conformal ultra-thin integrated phased array antenna according to claim 1, characterized in that: In step S2, when clamping the green tape (25), pin positioning is adopted.

5. The manufacturing process method of the fully conformal ultra-thin integrated phased array antenna according to claim 1, characterized in that: In step S3, during the warm water lamination operation, the preheating temperature of the shape-retaining lamination is 70 °C, the time is 60 min, and the lamination pressure is 262 Kgf / cm 2 , and the pressure is maintained for 10 min.

6. The manufacturing process method of the fully conformal ultra-thin integrated phased array antenna according to claim 1, characterized in that: In step S4, when the sintering temperature is below 450 °C, the heating rate ≤ 5 °C / s; when the sintering temperature is in the range of 450 °C to 850 °C, the heating rate is controlled at 5 °C / s to 8 °C / s.

7. The manufacturing process method of the fully conformal ultra-thin integrated phased array antenna according to claim 1, characterized in that: In step S4, when pressing the green ceramic tape (25) with the quartz pressing block (8), the pressure is 10 - 20Kgf / cm 2 .

8. The fully conformal ultra-thin integrated phased array antenna is obtained by the manufacturing process method of the fully conformal ultra-thin integrated phased array antenna according to any one of claims 1 to 7, and is characterized in that: It includes a base (1), a curved surface cavity is provided on one side of the base (1), a multi-layer LTCC curved surface substrate (2) is arranged in the curved surface cavity, and an antenna array (3) is arranged on the side of the multi-layer LTCC curved surface substrate (2) away from the base (1); several chips (4) are connected to the side of the multi-layer LTCC curved surface substrate (2) facing the base (1), several antenna radio frequency interfaces (5) are arranged on the antenna array (3), several via holes (21) are arranged in the multi-layer LTCC curved surface substrate (2), and wires connecting the chips (4) and the antenna radio frequency interfaces (5) are respectively arranged in the via holes (21).

9. The all-conformal ultra-thin integrated phased array antenna according to claim 8, wherein: Several grooves (22) are provided on the side of the multi-layer LTCC curved surface substrate (2) facing the base (1), the grooves (22) communicate with the via holes (21), and the chips (4) are mounted in the grooves (22).

10. The all-conformal ultra-thin integrated phased array antenna according to claim 8, characterized in that: A radio frequency main port (23) and a connector (24) are also provided on the side of the multi-layer LTCC curved surface substrate (2) facing the base (1).

Images