A method for gold plating of local insulating via holes in a fiberglass conformal radome

Abstract

The present invention relates to the field of conformal radome technology and specifically discloses a method for gold plating a partially insulated via hole in a fiberglass-reinforced plastic (FRP) conformal radome. The method involves drilling a hole into the FRP conformal radome to form an insulated via hole. A protective adhesive is used to partially protect the non-gold-plated portion of the FRP conformal radome. A copper layer, a nickel layer, and a gold layer are then sequentially plated within the insulated via hole. The protective layers are then removed to complete the gold plating. The method effectively ensures the conductivity and solderability of the insulated via hole. Furthermore, the resulting metal plating is completely plated within the insulated via hole, without affecting the overall shape and flatness of the FRP conformal radome.

Description

Technical Field

[0001] The present invention relates to the technical field of conformal antennas, and more particularly to a method for gold plating of local insulating via holes in a fiberglass reinforced plastic conformal antenna cover. Background Art

[0002] The fiberglass conformal radome is made by isolating and stacking a variety of single-sided circuit boards and composite materials and then co-molding them.

[0003] Currently, to ensure conductivity and solderability between the various circuit board layers, a highly conductive and solderable metal conductor is typically inserted and soldered through the vias of a conformal radome. This method makes the soldered metal conductors susceptible to external forces, disrupting the conformal antenna's overall shape and flatness, and affecting the radome's packaging. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a method for gold plating of localized insulating vias in a fiberglass-reinforced plastic (FRP) conformal radome. This method effectively ensures the conductivity and solderability of the insulating vias. Furthermore, the resulting metal coating is completely plated within the insulating vias, without affecting the overall shape and flatness of the FRP conformal radome.

[0005] The solution adopted by the present invention to solve the technical problem is:

[0006] A method for gold plating of local insulating vias of a fiberglass conformal radome comprises drilling holes in the fiberglass conformal radome to form insulating vias, using protective glue to locally protect non-gold-plated parts of the fiberglass conformal radome, sequentially plating copper layers, nickel layers, and gold layers in the insulating vias, then removing the protective layers to complete the gold plating.

[0007] In some possible implementations,

[0008] The specific steps include:

[0009] Step S1: drilling holes in the fiberglass conformal radome to form insulating vias;

[0010] Step S2: using protective glue to form a local protective layer to protect the portion of the fiberglass conformal radome that does not require gold plating, and processing the insulating vias;

[0011] Step S3: performing chemical copper deposition and copper plating in the insulating via hole in sequence to form a copper foil layer 1;

[0012] Step S4: removing the local protective layer 1 and trimming the insulating via hole plated with the copper foil layer 1;

[0013] Step S5: using protective glue to form a second protective layer to protect the parts of the fiberglass conformal radome that do not require local gold plating and expose the insulating vias;

[0014] Step S6: electroplating a copper layer, a nickel layer, and a gold layer in sequence on the insulating via hole;

[0015] Step S7: removing the local protective layer 2.

[0016] In some possible implementations,

[0017] The protective glue is a tearable plating-resistant glue; the viscosity of the tearable plating-resistant glue applied in a 4# cup is 5-10s.

[0018] In some possible implementations,

[0019] The thickness of the local protective layer 1 and the local protective layer 2 are both 100-150 μm.

[0020] In some possible implementations,

[0021] The processing of the insulating via in step S2 specifically includes the following steps:

[0022] Step S21: sandblasting the via holes; the sandblasting pressure is 0.2-0.4 MPa;

[0023] Step S22: removing the glue residue;

[0024] A mixed solution of potassium permanganate (45-60 g / L) and sodium hydroxide (30-40 g / L) is used for desmearing, wherein the temperature is 75-85°C and the treatment time is 10-15 minutes;

[0025] Step S23: chemical degreasing;

[0026] Chemical degreasing is performed using a detergent with a concentration of 40-60 g / L and a pore-regulating agent with a volume fraction of 5% of the total volume fraction of the mixed solution; wherein the temperature is 50-60° C. and the time is 6-10 minutes;

[0027] Step S24: palladium activation;

[0028] Use a mixture of pre-dip salt, hydrochloric acid, and activation solution to activate the insulating vias with palladium at a temperature of 20-40°C for 6-10 minutes.

[0029] Step S25: speeding up.

[0030] In some possible implementations,

[0031] The step S3 specifically includes the following steps:

[0032] Step S31: performing chemical copper deposition on the insulating vias using a chemical copper deposition solution at a temperature of 30-40° C. for 20-25 minutes;

[0033] Step S32: electroplating copper on the insulating vias with a copper plating solution at room temperature to form a copper foil layer 1; wherein the current density is 1.5-2.0A / dm 2 , time is 8-10min, and the thickness of the copper foil layer is 2-4μm.

[0034] In some possible implementations,

[0035] The step S6 specifically includes the following steps:

[0036] Step S61: inserting a plated lead into the insulating via hole;

[0037] Step S62: electroplating copper in the insulating via hole to form a second copper foil layer;

[0038] Step S63: electroplating nickel on the second copper foil layer to form a nickel-plated layer;

[0039] Step S64: electroplating gold on the nickel plating to form a gold-plated layer.

[0040] In some possible implementations,

[0041] The thickness of the copper foil layer 2 is at least 25 μm, and the electroplating is carried out at room temperature with a current density of 1.2-1.5 A / dm 2 , the electroplating time is 90-120min.

[0042] In some possible implementations,

[0043] The thickness of the nickel plating layer is at least 5 μm; during electroplating, the temperature is 50-60°C and the current density is 1.0-1.5A / dm 2 , the electroplating time is 25-30min.

[0044] In some possible implementations,

[0045] The thickness of the gold plating layer is at least 0.05 μm; during electroplating, the temperature is 45-55° C., and the current density is 0.2-0.4 A / dm 2 , the electroplating time is 1-3min.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention enables the insulating via hole to have good electrical conductivity and weldability by gold plating in the insulating via hole;

[0048] Compared with the existing technology of inserting and welding metal wires into insulating vias, the present invention avoids the metal strip wires being easily affected by external forces during the welding process, which may damage the overall shape and flatness of the conformal antenna and affect the packaging of the radome;

[0049] The present invention provides a copper foil layer 1 with a thickness of 2-4 μm in the insulating via hole, so that gold plating can be achieved in the insulating via hole. At the same time, due to the thin thickness of the copper foil layer 1, the local protective layer 1 and the copper foil layer 1 on the local protective layer 1 are easily removed without affecting the copper foil layer 1 in the insulating via hole.

[0050] The present invention protects the non-gold-plated parts of the glass fiber reinforced plastic collinear antenna cover by using a tearable plating-resist glue with a viscosity of 5-10s in a coating 4# cup. The glue has good viscosity and is not easy to spread, thus avoiding diffusion into the insulating via. DETAILED DESCRIPTION

[0051] In this application, unless otherwise specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integration; they can refer to direct connections or indirect connections through an intermediary; they can refer to internal communication between two components or interactions between two components. The terms "first," "second," and similar terms mentioned in this application do not denote any order, quantity, or importance; they are simply used to distinguish between different components. Similarly, terms such as "one" or "a" do not indicate a quantitative limitation; rather, they indicate the presence of at least one. In the implementation of this application, "and / or" describes an association relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more. For example, "plurality" refers to two or more positioning posts. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0052] The present invention is described in detail below.

[0053] Example 1:

[0054] A method for gold plating of local insulating vias of a fiberglass conformal radome comprises drilling holes in the fiberglass conformal radome to form insulating vias, using protective glue to locally protect non-gold-plated parts of the fiberglass conformal radome, sequentially plating copper layers, nickel layers, and gold layers in the insulating vias, then removing the protective layers to complete the gold plating.

[0055] By plating gold in the insulating vias, the insulating vias have good conductivity and solderability. At the same time, the generated metal plating is completely plated in the holes without affecting the overall shape and flatness of the fiberglass conformal antenna cover.

[0056] In some possible implementations,

[0057] The specific steps include:

[0058] Step S1: drilling holes in the fiberglass conformal radome to form insulating vias;

[0059] Step S2: using protective glue to form a local protective layer to protect the portion of the fiberglass conformal radome that does not require gold plating, and processing the insulating vias;

[0060] In some possible implementations, in order to effectively achieve bonding with the fiberglass reinforced plastics and effectively protect the non-gold-plated parts, and to effectively separate the two;

[0061] The protective glue is a tearable plating-resistant glue; the viscosity of the tearable plating-resistant glue applied in a 4# cup is 5-10s.

[0062] In some possible implementations,

[0063] The thickness of the local protective layer 1 and the local protective layer 2 are both 100-150 μm.

[0064] The insulating vias are processed in step S2 mainly to clean the insulating vias, and specifically include the following steps:

[0065] Step S21: sandblasting the via holes; the sandblasting pressure is 0.2-0.4 MPa;

[0066] Step S22: removing the glue residue;

[0067] A mixed solution of potassium permanganate (45-60 g / L) and sodium hydroxide (30-40 g / L) is used for desmearing, wherein the temperature is 75-85°C and the treatment time is 10-15 minutes;

[0068] Step S23: chemical degreasing;

[0069] Chemical degreasing is performed using a detergent with a concentration of 40-60 g / L and a pore-regulating agent with a volume fraction of 5% of the total volume fraction of the mixed solution; wherein the temperature is 50-60° C. and the time is 6-10 minutes;

[0070] Step S24: palladium activation;

[0071] Use a mixture of pre-dip salt, hydrochloric acid, and activation solution to activate the insulating vias with palladium at a temperature of 20-40°C for 6-10 minutes.

[0072] Step S25: Incubate at room temperature for 2-4 min.

[0073] Step S3: performing chemical copper deposition and copper plating in the insulating via hole in sequence to form a copper foil layer 1; in some possible implementations,

[0074] The step S3 specifically includes the following steps:

[0075] Step S31: performing chemical copper deposition on the insulating vias using a chemical copper deposition solution at a temperature of 30-40° C. for 20-25 minutes;

[0076] Step S32: electroplating copper on the insulating vias with a copper plating solution at room temperature to form a copper foil layer 1; wherein the current density is 1.5A / dm 2 , time is 8min, and the thickness of the copper foil layer is 2μm.

[0077] Step S4: removing the partial protective layer 1 and trimming the insulating via hole plated with the copper foil layer 1; specifically, using tweezers to remove the partial protective layer 1 and the copper foil layer on the partial protective layer 1 on the surface of the antenna cover to expose the insulating via hole plated with the copper foil layer 1;

[0078] Use a blade to remove the excess copper foil layer around the insulating via and trim the edge copper foil layer.

[0079] Step S5: using protective glue to form a second protective layer to protect the parts of the fiberglass conformal radome that do not require local gold plating and expose the insulating vias;

[0080] Step S6: electroplating a copper layer, a nickel layer, and a gold layer in sequence on the insulating via hole;

[0081] The step S6 specifically includes the following steps:

[0082] Step S61: inserting electroplating leads into the insulating vias; specifically, using ф0.2 copper wires as electroplating leads to connect the insulating vias to achieve the electroplating current conduction effect.

[0083] Step S62: Electroplating copper in the insulating via to form a second copper foil layer; the thickness of the second copper foil layer is 25 μm, and the electroplating is carried out at room temperature with a current density of 1.2 A / dm 2 , the electroplating time is 90min;

[0084] Step S63: electroplating nickel on the second copper foil layer to form a nickel-plated layer;

[0085] The thickness of the nickel plating layer is 5 μm; during electroplating, the temperature is 50° C., the current density is 1.0 A / dm 2 , the electroplating time is 25min.

[0086] Step S64: electroplating gold on the nickel plating to form a gold-plated layer;

[0087] The thickness of the gold plating layer is 0.05 μm; during electroplating, the temperature is 45° C. and the current density is 0.2 A / dm 2 , the electroplating time is 1min.

[0088] Step S7: removing the local protective layer 2 and cleaning; specifically, using tweezers to remove the local protective layer 2 on the surface of the antenna cover, removing the surface of the antenna cover, and cleaning the stains and foreign matter.

[0089] Example 2:

[0090] Compared with Example 1, this embodiment differs in that:

[0091] The thickness of the copper foil layer is 3 μm; the current density during electroplating of the copper foil layer is 1.7 A / dm 2 , time is 9 minutes;

[0092] The thickness of the second copper foil layer is 28 μm, and the current density of the first copper foil layer is 1.3 A / dm 2 , time is 110min;

[0093] The thickness of the nickel plating layer is 7 μm; during electroplating, the temperature is 55°C and the current density is 1.3 A / dm 2 , the electroplating time is 27min.

[0094] The thickness of the gold plating layer is 0.08μm; during electroplating, the temperature is 50℃ and the current density is 0.3A / dm 2 , the electroplating time is 2min.

[0095] Example 3:

[0096] Compared with Example 1 and Example 2, this embodiment differs in that:

[0097] The thickness of the copper foil layer is 4 μm; during electroplating, the current density is 2.0 A / dm 2 , time is 10 minutes,

[0098] The thickness of the second copper foil layer is 30 μm, and the electroplating is carried out at room temperature with a current density of 1.5 A / dm 2 , the electroplating time is 120min.

[0099] The thickness of the nickel plating layer is 10 μm; during electroplating, the temperature is 60°C and the current density is 1.5 A / dm 2 , the electroplating time is 30min.

[0100] The thickness of the gold plating layer is 0.10μm; during electroplating, the temperature is 55℃ and the current density is 0.4A / dm 2 , the electroplating time is 3min.

[0101] Comparative Example 1:

[0102] The difference between this embodiment and embodiments 1 to 3 is that:

[0103] The viscosity of the tearable resist coating in the 4# cup is 3s;

[0104] During chemical degreasing, a detergent having a concentration of 40-60 g / L and a pore-regulating agent having a volume fraction of 5% of the total volume fraction of the mixed solution are used for chemical degreasing; wherein, the temperature is 40° C. and the time is 15 minutes;

[0105] The insulating vias were treated with chemical copper plating solution at a temperature of 50°C for 20 minutes.

[0106] The thickness of the copper foil layer is 3 μm; the current density is 1.0 A / dm 2 , time is 15 minutes,

[0107] The thickness of the copper foil layer 2 is 15 μm, and the electroplating is carried out at room temperature with a current density of 1.0 A / dm 2 , the electroplating time is 90min.

[0108] The thickness of the nickel plating layer is 3 μm; during electroplating, the temperature is 40° C., the current density is 1.0 A / dm 2 , the electroplating time is 40min.

[0109] The thickness of the gold plating layer is 0.03 μm; during electroplating, the temperature is 40°C and the current density is 0.1 A / dm 2 , the electroplating time is 5min.

[0110] Comparative Example 2:

[0111] During chemical degreasing, a detergent having a concentration of 40-60 g / L and a pore-regulating agent having a volume fraction of 20% of the total volume fraction of the mixed solution are used for chemical degreasing; wherein, the temperature is 70° C. and the time is 5 minutes;

[0112] During chemical copper deposition, the insulating vias are treated with chemical copper deposition liquid at a temperature of 20°C for 35 minutes.

[0113] The thickness of the copper foil layer is 5 μm; the current density is 3 A / dm 2 The time is 3 minutes, the thickness of the copper foil layer 2 is 20 μm, and the electroplating is carried out at room temperature with a current density of 2 A / dm 2 , the electroplating time is 80min.

[0114] The thickness of the nickel plating layer is 5 μm; during electroplating, the temperature is 45° C., the current density is 0.8 A / dm2 , the electroplating time is 30min.

[0115] The thickness of the gold plating layer is 0.3 μm; during electroplating, the temperature is 30° C. and the current density is 0.3 A / dm 2 , the electroplating time is 2min.

[0116] Comparative Example 3:

[0117] The thickness of the copper foil layer is 4μm; during electroplating, the current density is 4A / dm 2 , time is 7 minutes,

[0118] The thickness of the second copper foil layer is 30μm, and the electroplating is carried out at room temperature with a current density of 3A / dm 2 , the electroplating time is 150min.

[0119] The thickness of the nickel plating layer is 10 μm; during electroplating, the temperature is 40°C and the current density is 2.5 A / dm 2 , the electroplating time is 10min.

[0120] The thickness of the gold plating layer is 0.10 μm; during electroplating, the temperature is 30°C and the current density is 0.7 A / dm 2 , the electroplating time is 5min.

[0121] According to the requirements of QJ 2776, the resistance requirement is not more than 10Ω. The above embodiments and comparative examples are tested for conductivity under the conditions of test voltage 200V and pressure 5S. According to the requirements of GJB362B, the test temperature is 235 +5 ℃, and the above examples and comparative examples were subjected to solderability tests. The test results of the electrical conductivity and solderability are shown in Table 1.

[0122]

[0123] Table 1

[0124] As can be directly seen in Table 1, the electrical conductivity and solderability of Examples 1-3 implemented according to the present invention are far superior to those of Comparative Examples 1-3. The present invention effectively ensures the electrical conductivity and solderability of the insulating vias. Furthermore, the resulting metal coating completely coats the insulating vias, without affecting the overall shape and flatness of the FRP conformal radome.

[0125] The present invention is not limited to the aforementioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A method for gold plating of local insulating via holes of a fiberglass conformal radome, characterized in that: Drilling holes in the fiberglass conformal radome to form insulating vias, using protective glue to partially protect the non-gold-plated parts of the fiberglass conformal radome, plating copper layers, nickel layers, and gold layers in the insulating vias in sequence, then removing the protective layers to complete the gold plating; specifically, the following steps are included: Step S1: drilling holes in the fiberglass conformal radome to form insulating vias; Step S2: using protective glue to form a local protective layer to protect the portion of the fiberglass conformal radome that does not require gold plating, and processing the insulating vias; The processing of the insulating via in step S2 specifically includes the following steps: Step S21: sandblasting the via holes; the sandblasting pressure is 0.2-0.4 MPa; Step S22: removing the glue residue; A mixed solution of potassium permanganate (45-60 g / L) and sodium hydroxide (30-40 g / L) is used for desmearing, wherein the temperature is 75-85°C and the treatment time is 10-15 minutes; Step S23: chemical degreasing; Chemical degreasing is performed using a detergent with a concentration of 40-60 g / L and a pore-regulating agent with a volume fraction of 5% of the total volume fraction of the mixed solution; wherein the temperature is 50-60° C. and the time is 6-10 minutes; Step S24: palladium activation; Use a mixture of pre-dip salt, hydrochloric acid, and activation solution to activate the insulating vias with palladium at a temperature of 20-40°C for 6-10 minutes. Step S25: speeding up; Step S3: performing chemical copper deposition and copper plating in the insulating via hole in sequence to form a copper foil layer 1; The step S3 specifically includes the following steps: Step S31: performing chemical copper deposition on the insulating vias using a chemical copper deposition solution at a temperature of 30-40° C. for 20-25 minutes; Step S32: electroplating copper on the insulating vias with a copper plating solution at room temperature to form a copper foil layer 1; wherein the current density is 1.5-2.0A / dm 2 , the time is 8-10min, and the thickness of the copper foil layer is 2-4μm; Step S4: removing the local protective layer 1 on the surface of the fiberglass radome and the copper foil layer 1 on the local protective layer 1, exposing the insulating via plated with the copper foil layer 1; Step S5: using protective glue to form a second protective layer to protect the parts of the fiberglass conformal radome that do not require local gold plating and expose the insulating vias; Step S6: Electroplating a copper layer, a nickel layer, and a gold layer in sequence on the insulating via hole; Step S6 specifically includes the following steps: Step S61: inserting a plated lead into the insulating via hole; Step S62: electroplating copper in the insulating via hole to form a second copper foil layer; Step S63: electroplating nickel on the second copper foil layer to form a nickel-plated layer; Step S64: electroplating gold on the nickel-plated layer to form a gold-plated layer; Step S7: removing the local protective layer 2.

2. The method for gold plating of local insulating via holes of a fiberglass conformal radome according to claim 1, characterized in that: The protective glue is a tearable plating-resistant glue; the viscosity of the tearable plating-resistant glue applied in a 4# cup is 5-10s.

3. The method for gold plating of local insulating via holes of a fiberglass conformal radome according to claim 1, characterized in that The thickness of the local protective layer 1 and the local protective layer 2 are both 100-150 μm.

4. The method for gold plating of local insulating via holes of a fiberglass conformal radome according to claim 1, characterized in that: The thickness of the copper foil layer 2 is at least 25 μm, and the electroplating is carried out at room temperature with a current density of 1.2-1.5 A / dm 2 , the electroplating time is 90-120min.

5. The method for gold plating of local insulating via holes of a fiberglass conformal radome according to claim 1, characterized in that: The thickness of the nickel plating layer is at least 5 μm; during electroplating, the temperature is 50-60°C and the current density is 1.0-1.5A / dm 2 , the electroplating time is 25-30min.

6. The method for gold plating of local insulating via holes of a fiberglass conformal radome according to claim 1, characterized in that: The thickness of the gold plating layer is at least 0.05 μm; during electroplating, the temperature is 45-55° C., and the current density is 0.2-0.4 A / dm 2 , the electroplating time is 1-3min.

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