Preparation method of light and small high-integration power amplifier module

Abstract

The invention relates to the technical field of power amplifier module manufacturing, in particular to a preparation method of a light and small high-integration power amplifier module, which comprises the following steps of: welding a connector and a shell: designing and selecting a solder ring matched with an assembly clearance for welding; performing surface-mount welding on the components: welding various required components on the circuit board by using automatic welding equipment through an SMT (surface mount technology) to form a circuit board assembly 1, a circuit board assembly 2,..., and a circuit board assembly n; one-time and multi-dimensional large-area brazing is conducted on the circuit board assemblies, wherein an independent integrated elastic welding tool is designed, and the multiple circuit board assemblies are welded to the shell at a time through welding equipment; assembling a power tube and other devices; according to the manufacturing method of the light and small high-integration power amplifier module, the problems that multiple times of step-by-step welding are needed, the manufacturing process is complex, the welding consistency is poor and the penetration rate is not high when a traditional method is used for implementing multi-dimensional welding of a circuit board are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power amplifier module manufacturing, and particularly relates to a preparation method for a lightweight and highly integrated power amplifier module. Background Art

[0002] Power amplifier modules are the core components of radio frequency and microsystems, and are widely used and in large quantities in electronic devices. The demand for a single set of equipment can reach tens of thousands. With the continuous improvement of equipment performance requirements, the demand for high-reliability and highly integrated small power amplifier modules is becoming increasingly urgent.

[0003] Power amplifier modules generally consist of a housing, a cover plate, a circuit board, power transistors, connectors, and components, etc. Their manufacturing process is complex. Just for welding alone, it covers multiple processes such as surface mount welding of components, large-area brazing of the circuit board, and plug-in welding. Compared with conventional power amplifiers, lightweight and highly integrated power amplifier modules have the characteristics of compact structure, small volume, high component density, and high heat dissipation requirements. The circuit board is replaced by multi-dimensional welding instead of the original simple and easy-to-implement screw connection, which improves the grounding and heat dissipation capabilities, but at the same time also increases the assembly difficulty and worsens the manufacturability. Specifically, it is manifested as: an increase in the number of welding times and solder types, easy re-melting of the solder, low welding accuracy, long cycle, especially when mass-producing, it is difficult to guarantee the product qualification rate and consistency. Therefore, how to achieve efficient and high-quality manufacturing and assembly of power amplifier modules in a narrow space is the key to improving the product qualification rate and ensuring the smooth progress of mass production.

[0004] In view of the above defects, the creator of the present invention finally obtained the present invention through long-term research and practice. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of multiple-step welding required, complex manufacturing processes, poor welding consistency, and low penetration rate when implementing multi-dimensional welding of the circuit board by traditional methods, and provides a preparation method for a lightweight and highly integrated power amplifier module.

[0006] To achieve the above purpose, the present invention discloses a preparation method for a lightweight and highly integrated power amplifier module, including the following steps:

[0007] S1, welding of the connector and the housing: Design and select a solder ring that matches the assembly gap for welding;

[0008] S2, surface mount welding of components: Through SMT technology, use an automated welding device to weld various required components onto the circuit board to form circuit board assemblies 1, circuit board assemblies 2,..., circuit board assemblies n;

[0009] S3, one-time and multi-dimensional large-area brazing of circuit board assemblies: Design an independent integrated elastic welding tooling, and weld multiple circuit board assemblies to the housing at one time through a welding device;

[0010] S4, Assemble the power transistor and other components;

[0011] S5, Detect the electrical performance and check whether the power within the specified frequency band meets the design requirements.

[0012] In step S1, the solder is Sn63Pb37 tin-lead solder, the housing material is copper alloy or aluminum alloy, and the welding temperature is 20 - 30 °C higher than the melting point of the solder.

[0013] In step S2, the material of the circuit board is TC350, SJ9350, or WL-CT35, and the solder paste for SMT is Sn63Pb37 or Sn62Pb36Ag2.

[0014] In step S3, it specifically includes the following steps:

[0015] S31, Design an integrated elastic welding tooling;

[0016] S32, Use a laser cutting machine to cut the solder sheet into a specific shape as the welding material;

[0017] S33, Fix and clamp the sample with the integrated tooling and place it on the welding equipment for welding;

[0018] S34, Before welding, the temperature of the circuit board needs to be measured with a thermometer;

[0019] S35, After welding, check the appearance of the weld seam and the penetration rate.

[0020] In step S31, the material of the tooling is copper alloy or aluminum alloy.

[0021] In step S32, the melting point of the solder sheet should be lower than that of the solder used in step S1 and the solder paste used in step S2, and the difference in melting points should be > 25 °C to avoid remelting of the solder.

[0022] In step S32, the solder sheet is SnPbIn solder sheet or InSn solder sheet.

[0023] In step S34, the temperature of the circuit board needs to meet the requirement that the temperature of each circuit board is higher than the melting point of the solder sheet, lower than the melting points of the solder used in step S1 and the solder paste used in step S2, and the temperature difference on each circuit board ≤ 2 °C.

[0024] In step S35, the weld seam should be well filled and the penetration rate ≥ 80%.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: When implementing multi-dimensional welding of multi-circuit board components in the existing power amplifier module manufacturing technology, multiple welding processes are required, the manufacturing process is complex, the welding consistency is poor, and problems such as solder remelting and low welding penetration rate are likely to occur, which restricts the improvement of production efficiency and product qualification rate during module batch production. The power amplifier module manufacturing method proposed by the present invention is more scientific and reasonable in the manufacturing process, not only shortening the manufacturing time and cost, but also greatly improving the product quality and production efficiency of batch production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the process flow chart of the preparation of the present invention;

[0027] Figure 2 is the front view of the power amplifier module in Embodiment 1;

[0028] Figure 3 is the back view of the power amplifier module in Embodiment 1;

[0029] Figure 4 is the process flow chart of the preparation of the power amplifier module in Embodiment 1;

[0030] Figure 5 is the fixture clamping schematic diagram of the power amplifier module in Embodiment 1;

[0031] Figure 6 is the schematic diagram of the power amplifier module in Embodiment 2;

[0032] Figure 7 is the process flow chart of the preparation of the power amplifier module in Embodiment 2;

[0033] Figure 8 is the fixture clamping schematic diagram of the power amplifier module in Embodiment 2.

[0034] The numbers in the figure represent:

[0035] 1 - housing; 2 - front circuit board; 3 - first power transistor; 4 - bottom insulator; 5 - side insulator; 6 - second power transistor; 7 - back circuit board; 8 - first circuit board; 9 - second circuit board; 10 - third circuit board; 11 - power transistor; 12 - insulator; 13 - RF cable; 14 - rigid support plate; 15 - elastic pressure point; 16 - connecting column; 17 - fixed pressure point; 18 - power amplifier module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The following further describes in detail the above and other technical features and advantages of the present invention with reference to the accompanying drawings.

[0037] Embodiment 1

[0038] The implementation object of this embodiment is the power amplifier module 1, asFigure 2 and Figure 3 As shown. It is composed of a housing 1, a front circuit board 2, a back circuit board 7, a first power transistor 3, a second power transistor 6, a bottom insulator 4, a side insulator 5 and other components. The manufacturing process involves multi-dimensional high-precision welding of circuit boards and insulators. The power amplifier has a power ≥ 400W and high heat dissipation requirements, and the penetration rate requirement is ≥ 90%.

[0039] The power amplifier housing and the circuit board substrate are respectively made of copper alloy with high thermal conductivity and SJ9350 domestic sheet. The manufacturing process is as shown in the appendix Figure 4 shown, and the main steps include:

[0040] (1) Use a Sn63Pb37 solder ring to weld the bottom insulator to the housing through a hot stage.

[0041] (2) Use Sn63Pb37 solder paste to surface-mount the components onto the front circuit board and the back circuit board through SMT technology.

[0042] (3) Design an integrated tooling (see Figure 5 ), including a rigid support plate 14, elastic pressure points 15, connecting columns 16, fixed pressure points 17, and a power amplifier module 18. Use a SnPbIn solder sheet as the solder and weld the front circuit board and the back circuit board to the housing at one time through a reflow furnace.

[0043] (4) Use a SnPbIn solder ring to weld the side insulator to the housing through a hot stage.

[0044] (5) Assemble the first power transistor, the second power transistor and other devices to obtain a complete power amplifier module.

[0045] Only two high and medium melting point solders, Sn63Pb37 and SnPbIn, are used in the entire manufacturing process of the power amplifier module. They have good high-temperature mechanical properties and low remelting risk. An integrated welding tooling is designed to clamp and fix the power amplifier (see Figure 3 ). The tooling is made of oxygen-free copper material with good thermal conductivity. The front and back circuit board assemblies and the housing after clamping are welded into shape at one time through a reflow furnace. The furnace temperature curve is measured before welding to ensure the welding quality and avoid problems such as component damage, long welding cycle, and poor welding accuracy caused by multiple weldings. After testing, the penetration rate is ≥ 90%, and the power meets the requirement of ≥ 400W in the working frequency band.

[0046] Example 2

[0047] The implementation object of this example is the power amplifier module 2, as shown in Figure 6As shown in the figure, it is composed of a housing 1, a first circuit board 8, a second circuit board 9, a third circuit board 10, a power transistor 11, an insulator 12 and other components (such as a radio frequency cable 13). The manufacturing process involves high-precision welding of multiple thicknesses and dimensions of circuit boards. The power of this power amplifier is ≥210W, and the requirement for the penetration rate is ≥80%.

[0048] The power amplifier module internally contains three circuit boards with different thicknesses (1.1mm, 0.82mm, and 0.58mm), all arranged on the same plane of the housing. The housing and the circuit boards are respectively made of aluminum alloy and WL-CT350 material, with good heat dissipation effect. The manufacturing process of the power amplifier module is as Figure 7 shown, and the main steps include:

[0049] (1) Use Sn63Pb37 solder paste to surface-mount components onto circuit board 1, circuit board 2, and circuit board 3 through SMT technology.

[0050] (2) Design an integrated welding tooling (see Figure 8 ), including a rigid support plate 14, elastic pressure points 15, connecting columns 16, and a power amplifier module 18. Use SnPbIn solder sheet as the solder, and weld circuit board 1, circuit board 2, and circuit board 3 to the housing at one time through a reflow oven.

[0051] (3) Use SnPbIn solder rings to weld the insulator to the housing with a hot stage.

[0052] (4) Assemble the power transistor and other devices to obtain a complete power amplifier module.

[0053] Benefiting from the advantages of the integrated elastic welding tooling, the three circuit board assemblies are welded into shape at one time through a hot stage or a reflow oven. The elastic pressure points of the elastic tooling can generate adaptive pressure on circuit boards of different thicknesses, upgrading the original need for three kinds of solder and three weldings to one kind of solder and one forming, significantly improving the welding efficiency and precision. The penetration rate after welding is >80%, and the power under the working frequency band meets the requirement of ≥210W.

[0054] The above is only the preferred embodiment of the present invention, which is illustrative rather than restrictive to the present invention. Those skilled in the art understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, but all will fall within the protection scope of the present invention.

Claims

1. A method for preparing a lightweight, small, highly integrated amplifier module, characterized in that: The following steps are involved: S1, welding of connector and housing: design and select solder ring matching the assembly gap for welding; S2, surface mount welding of components: through SMT technology, using automated welding equipment, various required components are welded to the circuit board to form circuit board assembly 1, circuit board assembly 2, ..., circuit board assembly n; S3, one-time, multi-dimensional large-area brazing of circuit board components: design an independent integrated elastic welding tool to weld multiple circuit board components to the shell at one time through welding equipment; S4, assemble power tubes and other devices; S5, test the electrical performance and examine whether the power within the frequency band meets the design requirements.

2. The method for preparing a light and small-sized highly integrated amplifier module according to claim 1, characterized in that: In the step S1, the solder is tin-lead solder Sn63Pb37, the shell material is copper alloy or aluminum alloy, and the welding temperature is 20-30° C. higher than the melting point of the solder.

3. The method for preparing a light and small-sized highly integrated amplifier module according to claim 1, characterized in that: In the step S2, the material of the circuit board is TC350, SJ9350, or WL-CT35, and the solder paste used for SMT is Sn63Pb37 or Sn62Pb36Ag2.

4. The method for preparing a light and small-sized highly integrated amplifier module according to claim 1, characterized in that: The step S3 specifically includes the following steps: S31, design of integrated elastic welding tooling; S32, using a laser cutting machine to cut the welding sheet into a specific shape as welding material; S33, fix and clamp the sample by integrated tooling and place it on the welding equipment for welding; S34, before welding, the temperature of the circuit board needs to be measured with a thermometer; S35, check weld appearance and penetration after welding.

5. The method for preparing a light and small-sized highly integrated amplifier module according to claim 4, characterized in that: In the step S31, the tooling material is copper alloy or aluminum alloy.

6. The method for preparing a light and small-sized highly integrated amplifier module according to claim 4, characterized in that: In step S32, the melting point of the solder sheet should be lower than that of the solder used in step S1 and the solder paste used in step S2, and the difference in melting points should be greater than 25°C to avoid remelting of the solder.

7. The method for preparing a light and small-sized highly integrated amplifier module according to claim 4, characterized in that: In the step S32, the soldering sheet is a SnPbIn soldering sheet or an InSn soldering sheet.

8. The method for preparing a light and small-sized highly integrated amplifier module according to claim 4, characterized in that: In step S34, the temperature of each circuit board must be higher than the melting point of the solder sheet and lower than the melting point of the solder used in step S1 and the solder paste used in step S2, and the temperature difference on each circuit board is ≤2°C.

9. The method for preparing a light and small-sized highly integrated amplifier module according to claim 4, characterized in that: In step S35, the weld should be well filled and the penetration rate should be ≥80%.

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