Method for controlling water vapor content inside highly integrated microwave components

Abstract

The present invention discloses a method for controlling the internal water vapor content of a highly integrated microwave component. First, a substrate material with a water absorption rate of no more than 0.02% is selected as a multi-layer hybrid circuit board, and a plurality of non-metallic exhaust holes are arranged on the multi-layer hybrid circuit board, and the non-metallic exhaust holes penetrate the multi-layer hybrid circuit board to obtain a semi-finished multi-layer hybrid circuit board; then a sealed connector is sintered to a microwave component housing; the semi-finished multi-layer hybrid circuit board is de-watered and baked at high temperature; secondly, the parts are assembled in the microwave component housing; the microwave component is de-watered and baked at high temperature before capping; and finally the microwave component housing is capped. The present invention can control the internal water vapor content of the microwave component within 500ppm after being stored for 20 years, thereby improving the service life and reliability of the internal components.

Description

Technical Field

[0001] The invention relates to the technical field of micro-assembly, in particular to a method for controlling water vapor content inside a high-integration microwave component. Background Art

[0002] As a key component in the whole system, microwave components are required to develop in the direction of low power consumption, miniaturization and high integration with the development of navigation and microwave communication. High-integration microwave components use micro-assembly technology to achieve high-density interconnection of integrated circuit chips, chip resistors / capacitors / inductors and other components through multi-layer mixed-pressure circuit boards, and are encapsulated in the same component housing to become high-density microelectronic products. However, due to the complexity of the application environment of high-integration microwave components and the water vapor problem inside them, the reliability of high-integration microwave components is greatly affected.

[0003] When the water vapor content inside a highly integrated microwave component is high, it will not only cause additional surface leakage and related secondary effects, but also produce hydrolysis or electrochemical reactions with salts, causing corrosion of the integrated circuit chip inside the component. Therefore, water vapor is an important factor affecting the reliability of highly integrated microwave components. With the development of microsystems in the direction of high integration and high reliability, the requirements for micro-assembly reliability are getting higher and higher. How to strengthen the control of water vapor content inside highly integrated microwave components is an urgent problem to be solved.

[0004] The existing technology usually controls water vapor in sealed cavities or ceramic package modules in the form of tube shells, but the size of such components and modules is small (usually: ≤11mm×11mm×3mm), the function is single, no new circuit board materials are introduced into the tube shell, no multi-core low-frequency connectors, and the number of components is small (usually: ≤5), so the source of water vapor introduction is very single, so it is relatively easy to control the water vapor content inside the closed cavity in the form of tube shells. Even if the water vapor content reaches a certain standard in a short period of time, the water vapor content cannot be controlled after long-term storage. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a method for controlling the internal water vapor content of a highly integrated microwave component, which can control the water vapor content within 500 ppm and still control it within 500 ppm after storage for 20 years.

[0006] Technical solution: The method for controlling the water vapor content inside a highly integrated microwave component of the present invention comprises the following steps:

[0007] (1) Low-water vapor multi-layer hybrid circuit board: A substrate material with a water absorption rate of no more than 0.02% is selected as the multi-layer hybrid circuit board, and a plurality of non-metallic exhaust holes are provided on the multi-layer hybrid circuit board, wherein the non-metallic exhaust holes penetrate the multi-layer hybrid circuit board to obtain a semi-finished multi-layer hybrid circuit board;

[0008] (2) Sintering the sealed connector to the microwave component housing;

[0009] (3) High temperature baking of semi-finished multi-layer mixed-pressed circuit boards to remove moisture;

[0010] (4) Assembling the parts in the microwave assembly housing;

[0011] (5) Remove moisture from the microwave components and bake at high temperature before sealing them;

[0012] (6) Sealing cap of microwave component housing.

[0013] Furthermore, in step (1), the number of the non-metallized exhaust holes is ≥ 1 / 100 mm 2 .

[0014] Furthermore, in step (3), the multi-layer mixed-pressed circuit board semi-finished product is baked at a high temperature to remove moisture at a temperature of 110° C. to 130° C. and a baking time of 4 h to 6 h.

[0015] Furthermore, in step (5), the microwave component is baked at a high temperature to remove moisture before capping, and the baking temperature is 110° C. to 130° C. and the baking time is 48 h to 72 h.

[0016] Furthermore, in step (2), the sealed connector is sintered on the microwave component housing by a gold-tin process, the sintering solder is Au80Sn20, the sintering temperature is 300±10°C, the transition temperature is 150±10°C, and the sintering time is not less than 1 minute. After sintering, the sealed connector is blown with helium for airtightness inspection; if the airtightness inspection requirements are not met, the leakage position is checked and step (2) is re-executed.

[0017] Furthermore, in step (4), the semi-finished multilayer hybrid circuit board, the integrated circuit chip and the circuit elements are assembled in a microwave component housing.

[0018] Furthermore, in step (6), after the cap is sealed, the microwave assembly is tested for air tightness; if the air tightness test requirements are not met, the leak location is checked, the cap is opened, and steps (5) and (6) are re-executed.

[0019] Furthermore, the air tightness test requires that the leakage rate is no more than 10.1×10-9 Pa·m3 / s.

[0020] The electronic device described in the present invention includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded into the processor, the method for controlling the internal water vapor content of a highly integrated microwave component is implemented.

[0021] The computer-readable storage medium of the present invention stores a computer program, and when the computer program is executed by a processor, the method for controlling the internal water vapor content of a highly integrated microwave component is implemented.

[0022] Beneficial effects: Compared with the prior art, the advantages of the present invention are: the present invention provides a channel for the release of internal water vapor during the baking process of the multi-layer mixed pressure circuit board by setting a microwave substrate with low water absorption rate and non-metallized exhaust holes; the sealed connector is sintered to the component housing, and the laser sealing cap of the microwave component housing ensures that the component has good sealing characteristics, and prevents the finished component from leaking air and water vapor from entering the component. The present invention can increase the water vapor content of the highly integrated microwave component from 5000ppm to less than 500ppm, exponentially improving the service life and reliability of the components inside the component. The accelerated life test confirms that the water vapor content inside the component is still controlled within 500ppm after 20 years of storage, filling the engineering technology gap in this field. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart of the method for controlling water vapor content inside a highly integrated microwave component of the present invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0025] like Figure 1 As shown, the water vapor content control method of the present invention is aimed at a high-integration microwave component. The closed cavity of the high-integration microwave component is in the form of a component shell. The component shell is relatively large in size (usually ≥50mm×50mm×10mm), and the functions are complex. A multi-layer mixed-pressure circuit board (the main source of water vapor) is introduced into the component, and there are different types of connectors and a large number of components (usually ≥1000). Therefore, the source of water vapor introduction is very complex. In addition, due to the large variety of materials inside the component, complex circuit principles, and complex process steps, the baking temperature of the component cannot exceed 140°C (when baking exceeds 140°C, the low-temperature solder inside the component will remelt and the reliability of individual components will be reduced). In short, it is difficult to control the water vapor content inside a closed cavity in the form of a component shell, especially to overcome the problem of controlling the internal water vapor content after the component has been stored for an extended period of time.

[0026] The method for controlling water vapor content inside a highly integrated microwave component of the present invention comprises the following steps:

[0027] (1) Low-water vapor multi-layer hybrid circuit board: Select microwave substrates with a water absorption rate of ≤0.02% to manufacture multi-layer hybrid circuit boards. Evenly arrange non-metallic exhaust holes on the multi-layer hybrid circuit boards. The non-metallic exhaust holes run through the top layer to the bottom layer of the multi-layer hybrid circuit board. The number of exhaust holes is ≥1 / 100mm.2 .

[0028] A non-metallized through hole is a hole that is simply drilled in the post-production process of the board. The inner wall of the hole has no metal (usually copper).

[0029] The microwave substrate with low water absorption reduces the inhalation of water vapor in the air during the production process. The non-metallized vent holes provide a channel for the release of internal water vapor during the baking process of the multi-layer mixed pressure circuit board. The lower the water absorption rate of the microwave substrate and the more non-metallized vent holes, the shorter the baking time required. However, as the number of non-metallized holes increases, the integration of the components will also decrease. At the same time, the microwave substrate with low water absorption and non-metallized vent holes can also reduce the baking temperature and baking time. The lower baking temperature and baking time also improve the reliability of the components. In addition, since the multi-layer mixed pressure circuit board takes into account both the low-frequency power supply signal and the high-frequency microwave signal wiring, the multi-layer mixed pressure circuit board is required to be metallized (similar to a metal wall) to further reduce the water vapor release path.

[0030] (2) Sealed connector sintered to the component housing: The sealed connector is sintered to the component housing by a gold-tin process, with sintering solder: Au80Sn20, sintering temperature: (300±10)℃, transition temperature: (150±10)℃, sintering time: ≤1 minute. After sintering, the sealed connector is blown with helium for air tightness test, and the leakage rate is less than 10.1×10 -9 Pa·m 3 / s. Otherwise, it is necessary to check the leaking location and repair the leak with solder or re-sinter the leaking location until the leak rate index requirements are met.

[0031] (3) High-temperature baking to remove moisture from the semi-finished multi-layer mixed-pressed circuit board: Before being assembled in the component housing, the semi-finished multi-layer mixed-pressed circuit board is baked in a high-temperature oven to remove moisture at a temperature of 110°C to 130°C for a time of 4h to 6h.

[0032] (4) Parts are assembled in the component housing: semi-finished multi-layer mixed-pressure circuit boards, integrated circuit chips, chip resistors / capacitors / inductors and other parts are assembled in the component housing.

[0033] (5) High-temperature baking to remove moisture from the microwave component before capping: The microwave component is baked at a high temperature to remove moisture before capping, with a baking temperature of 110°C to 130°C and a baking time of 48h to 72h.

[0034] (6) Laser sealing of microwave component housing: The microwave component housing is laser sealed. After sealing, the microwave component seal is subjected to coarse and fine leak detection. The leakage rate is required to be less than 10.1×10 -8 Pa·m 3 / s. Otherwise, a leak check is required, the component cap is opened, and steps (5) and (6) are repeated until the requirements are met.

[0035] Next, a series of experiments were performed to verify the method of the present invention. The experimental conditions and parameters of this experiment were limited as follows:

[0036] 1. The multi-layer hybrid circuit board and the low-water vapor multi-layer hybrid circuit board used in the test are the same (including dimensions, circuits, manufacturing processes, etc.) except for the substrate material and non-metallized vent holes;

[0037] 2. The inner cavity volume of the component is 22.4cm3, and the size of the multi-layer mixed pressure circuit board is approximately: 54mm×40mm×1.0mm;

[0038] 3. The components include sealed connector J63AMI-2S1-025-8A1-DZ2, semi-finished multi-layer mixed-pressure circuit boards, integrated circuit chips, resistors / capacitors / inductors and other parts;

[0039] 4. The component capping is laser capping, and the sealing after the component capping meets the requirements of GJB 360B-2009 Method 112 for fine leak detection: Condition C, rough leak detection: Condition E;

[0040] 5. The component shell is made of aluminum alloy 6061 and the cover is made of aluminum alloy 4047;

[0041] 6. The water vapor content of the components shall be ≤5000ppm in accordance with GJB 548C-2021 Method 1018.

[0042] The test conditions and test results are shown in Table 1. In the title of Table 1, "Whether it is low water vapor" means "whether it is a low water vapor multilayer mixed pressure circuit board", "Whether it is sintered" means "whether the sealed connector is sintered in the component housing", "Whether the semi-finished product is baked" means "whether the multilayer mixed pressure circuit board semi-finished product is baked at high temperature to remove water vapor", "Whether to bake before capping" means "whether the microwave component is baked at high temperature to remove water vapor before capping the temperature and time", "1st day" means "the water vapor content inside the component is measured on the 1st day after capping", "60th day" means "the water vapor content inside the component is measured on the 60th day after capping", and "20 years" means "the water vapor content inside the component is measured 20 years after capping (equivalent to accelerated life test)".

[0043] Table 1 Test conditions and test results

[0044]

[0045]

[0046]

[0047]

[0048] Since water vapor detection is usually carried out destructively (by piercing a hole in the cover plate for water vapor detection), the same component test requires repeated uncapping, baking, laser capping, etc., which affects the test progress and accuracy. Therefore, three microwave components with the same conditions were used to conduct water vapor detection 1 day, 60 days and 20 years after capping under the same test conditions.

[0049] It can be seen from the above test results that if there is no non-metallized exhaust hole, the internal water vapor cannot be completely removed by simply setting the baking temperature to 100-150°C and the baking time to 200-300 minutes.

[0050] The substrate material used in components 1# to 4# has a water absorption rate of 0.22%, and no non-metallized exhaust holes are set. It is baked at high temperature with water vapor before capping. According to the test results, even if it is baked for 48 hours, the internal water vapor content on the first day after capping can only reach 11500ppm.

[0051] The substrate material used in components 5# to 36# has a water absorption rate of 0.02% and is provided with non-metallized exhaust holes.

[0052] Component 5# was not subjected to high-temperature baking before capping of the semi-finished multi-layer mixed-pressed circuit board and the microwave component. The water vapor content measured on the first day after capping was 36,000 ppm.

[0053] Before the microwave components were capped, components 6# to 8# were baked at 90°C for 16h, 24h and 48h respectively. It can be seen that the water vapor content decreased from 15500ppm to 4300ppm.

[0054] Before microwave capping, components 9#~15# were baked at 120℃ for 16h, 24h and 48h respectively. It can be seen that the water vapor content decreased from 4500ppm to 420ppm. However, when measured 60 days after capping, the water vapor content increased. 20 years after capping, even the microwave component (15#) baked for 48h had a water vapor content increase of 540ppm.

[0055] The multi-layer mixed-pressure circuit boards of components 16#~21# were baked at 110℃ for 4h and 6h respectively, and baked at 110℃ for 48h before capping. According to the test results, the water vapor content was controlled within 500ppm 20 years after capping. The water vapor content of component 21# was 390ppm 20 years after capping.

[0056] The multi-layer mixed-pressure circuit boards of components 22#~27# were baked at 120℃ for 4h and 6h respectively, and baked at 120℃ for 48h before capping. According to the test results, the water vapor content was controlled within 500ppm 20 years after capping. The water vapor content of component 27# was 380ppm 20 years after capping.

[0057] The multi-layer mixed-pressure circuit boards of components 28#~33# were baked at 130℃ for 4h and 6h respectively, and baked at 130℃ for 48h before capping. According to the test results, the water vapor content was controlled within 500ppm 20 years after capping. The water vapor content of component 33# was 350ppm 20 years after capping.

[0058] The multi-layer mixed-pressure circuit boards of components 34#~36 were baked at 130℃ for 6 hours, and baked at 130℃ for 72 hours before capping. According to the test results, the water vapor content can be controlled within 500ppm 20 years after capping. The water vapor content of component 36# 20 years after capping is 320ppm.

Claims

1. A method for controlling water vapor content inside a highly integrated microwave component, characterized in that: The steps include: (1) Low-water vapor multi-layer hybrid circuit board: A substrate material with a water absorption rate of no more than 0.02% is selected as the multi-layer hybrid circuit board, and a plurality of non-metallic exhaust holes are provided on the multi-layer hybrid circuit board, wherein the non-metallic exhaust holes penetrate the multi-layer hybrid circuit board to obtain a semi-finished multi-layer hybrid circuit board; (2) Sintering the sealed connector to the microwave component housing; (3) High temperature baking of semi-finished multi-layer mixed-pressed circuit boards to remove moisture; (4) Assembling the semi-finished multilayer hybrid circuit board, integrated circuit chips and circuit components in a microwave component housing; (5) Remove moisture from the microwave components and bake at high temperature before sealing them; (6) Sealing cap of microwave component housing.

2. The method for controlling water vapor content inside a highly integrated microwave component according to claim 1, characterized in that: In step (1), the number of the non-metallized exhaust holes is ≥ 1 / 100mm 2 .

3. The method for controlling water vapor content inside a highly integrated microwave component according to claim 1, characterized in that: In step (3), the baking temperature of the semi-finished multi-layer mixed-pressed circuit board to remove moisture is 110° C. to 130° C. and the baking time is 4 h to 6 h.

4. The method for controlling water vapor content inside a highly integrated microwave component according to claim 1, characterized in that: In step (5), the microwave component is baked at a high temperature to remove moisture before capping, and the baking temperature is 110° C. to 130° C. and the baking time is 48 h to 72 h.

5. The method for controlling water vapor content inside a highly integrated microwave component according to claim 1, characterized in that: In step (2), the sealed connector is sintered on the microwave component housing by a gold-tin process, the sintering solder is Au80Sn20, the sintering temperature is 300±10°C, the transition temperature is 150±10°C, and the sintering time is not less than 1 minute. After sintering, the sealed connector is blown with helium for air tightness inspection; if the air tightness inspection requirements are not met, check the leakage position and re-execute step (2).

6. The method for controlling water vapor content inside a highly integrated microwave component according to claim 1, characterized in that: In step (6), after sealing the cap, the microwave assembly is tested for air tightness; if the air tightness test requirements are not met, the leak location is checked, the cap is opened, and steps (5) and (6) are performed again.

7. The method for controlling water vapor content inside a highly integrated microwave component according to claim 5 or 6, characterized in that: The air tightness test requires that the leakage rate is no greater than 10.1×10-9Pa·m3 / s.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the computer program is loaded into a processor, the method for controlling water vapor content inside a highly integrated microwave component according to any one of claims 1 to 7 is implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for controlling the internal water vapor content of a highly integrated microwave component according to any one of claims 1 to 7 is implemented.

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