Metallization process of miniaturized LTCC waveguide filter

Abstract

The invention discloses a metallization process of a miniaturized LTCC waveguide filter. The metallization process comprises the steps of injecting silver into a preformed hole and spraying silver on the surface; the step of injecting silver into the preformed hole comprises the substeps that silver is injected into the preformed hole of the device, so that the inner surface of the preformed hole is covered with silver paste; the surface silver spraying comprises the step of spraying silver on the outer surface of the device after silver injection in the preformed hole is completed. According to the method, the process mode of combining silver injection and silver spraying is adopted, and it can be effectively guaranteed that the inner surface of the hole is completely coated, and the overall thickness is uniform and controllable; the preparation process is simple, the reproducibility is good, the cost is low, the performance is excellent, and the application is wide.

Description

Technical Field

[0001] The invention relates to a metallization process for a miniaturized LTCC waveguide filter. Background Art

[0002] Miniaturized LTCC waveguide filters are highly integrated filter devices that are achieved through low-temperature co-fired ceramic (LTCC) three-dimensional integration technology. Due to the nature of the material, the device surface does not have good conductivity and corrosion resistance, so a layer of metal needs to be added to its surface to achieve the connection between the device and the external circuit. Therefore, metallization is a necessary means to connect the device to the external circuit, and the external connection of the device must be achieved through metallization. In addition, metallization can also improve the electrical performance and reliability of the device, and it is also meaningful to enhance the reliability of the device in harsh environments such as high temperature and humidity.

[0003] At present, dielectric waveguide metallization can be achieved by printing, silver injection, silver spraying, immersion silver and other processes. Among them, the printing process requires the surface of the device to be flat, and it is difficult to coat the reserved holes; and the immersion silver process is difficult to control the thickness of the silver layer on the surface of the device. Therefore, it is necessary to optimize the design of the metallization process of miniaturized LTCC waveguide filters. Summary of the invention

[0004] In order to solve the defects of the prior art, the present invention provides a metallization process for a miniaturized LTCC waveguide filter, including silver injection in a reserved hole and silver spraying on the surface; The step of injecting silver into the reserved hole comprises: injecting silver into the reserved hole of the device so that the inner surface of the reserved hole is covered with silver paste; The surface spraying of silver comprises: after silver is injected into the reserved hole, spraying silver on the outer surface of the device.

[0005] Preferably, in the step of injecting silver into the reserved holes, a dispensing machine is used to inject silver into the reserved holes of the device.

[0006] Preferably, in the surface silver spraying step, silver is sprayed on the outer surface of the device using a metal spray gun.

[0007] Preferably, in the surface silver spraying step, silver is sprayed on six surfaces of the device in turn.

[0008] Preferably, in the surface silver spraying step, the thickness of the silver layer on the outer surface of the device is controlled by selecting the gun head model, spraying speed and number of spraying of the metal spray gun.

[0009] Preferably, before silver is injected into the reserved hole, surface treatment is first performed; The surface treatment comprises: placing the device in a ball milling jar, and adding molybdenum dioxide, zirconium oxide balls and pure water; grinding the device for a certain period of time by a jar grinder, discharging the material, cleaning it, and then ultrasonically cleaning and drying it to obtain a smooth and clean device; Preferably, in the surface treatment step, grinding is performed by a jar grinder for 3 hours.

[0010] Preferably, after the surface silver is sprayed, silver baking and silver sintering are also performed; The silver baking and silver burning comprises: placing the device after the surface of the device is sprayed with silver into a silver baking furnace for drying, and after drying, sending the device into the silver burning furnace for silver burning.

[0011] The advantages and beneficial effects of the present invention are: providing a metallization process for a miniaturized LTCC waveguide filter, adopting a process combining silver injection and silver spraying, which can effectively ensure that the inner surface of the hole is completely coated and the overall thickness is uniform and controllable; and the preparation process of the present invention is simple, reproducible, low cost, excellent performance, and widely applicable.

[0012] The present invention also has the following characteristics: 1) The surface treatment step of the present invention can make the edges and corners of the device rounded, improve the problem of too thin silver layer or even no silver at the edges and corners of the device; and can clean the surface of the device, remove impurities and stains on the surface, so as to improve the efficiency and quality of device metallization.

[0013] 2) Compared with the traditional device overall silver immersion process, the step of injecting silver into the reserved hole of the present invention can make the thickness of the silver layer on the surface of the reserved hole more uniform; and can avoid the situation where bubbles are generated in the reserved hole when the device is overall silver-immersed, resulting in local silver deficiency; this step is also applicable to the surface coating of other devices with reserved positions (such as small through holes, stepped holes, etc.).

[0014] 3) The surface silver spraying step of the present invention can control the required silver layer thickness by selecting the spray gun head model, spray speed and spray times, and is more flexible in adjusting the thickness requirements of different devices.

[0015] 4) The silver baking and silver sintering steps of the present invention solidify the silver on the device surface, and the silver layer has a certain adhesion to the device.

[0016] 5) The material obtained by the formula and process adopted in the present invention can be co-fired with silver electrodes at a temperature below 900°C. DETAILED DESCRIPTION

[0017] The specific implementation of the present invention is further described below in conjunction with the examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and cannot be used to limit the protection scope of the present invention.

[0018] The technical solutions specifically implemented in the present invention are as follows: A metallization process for a miniaturized LTCC waveguide filter comprises the following steps: 1) Surface treatment The device (i.e., ceramic blank) is placed in a ball mill, and molybdenum dioxide, zirconium oxide balls and pure water are added; the device is ground by a jar grinder for 3 hours, then discharged, cleaned, ultrasonically cleaned, and dried to obtain a smooth and clean device; This step (surface treatment) can make the device edges and corners rounded, improve the problem of too thin silver layer or even no silver at the corners of the device; and clean the device surface, remove surface impurities and stains, etc., to improve the efficiency and quality of device metallization; 2) Silver injection in the reserved hole Use a dispensing machine to inject silver into the reserved holes of the device so that the inner surface of the reserved holes is covered with silver paste; Compared with the traditional silver immersion process of the whole device, this step (silver injection in the reserved hole) can make the thickness of the silver layer on the surface of the reserved hole more uniform; and it can avoid the situation where the part is lack of silver due to bubbles in the reserved hole when the whole device is silver-immersed; this step is also applicable to the surface coating of other devices with reserved positions (such as small through holes, stepped holes, etc.); 3) Silver spraying on the surface After silver is injected into the reserved holes, use a metal spray gun to spray silver on the outer surface of the device (spray silver on the six sides of the device in turn); In this step (surface silver spraying), the thickness of the silver layer on the outer surface of the device can be controlled by selecting the spray gun head model, spray speed and spray times, which is more flexible to adjust the thickness requirements of different devices; 4) Silver baking and silver burning The device after the surface silver spraying is placed in a silver drying furnace for drying, and after drying, the device is sent to a silver burning furnace for silver burning; This step (silver baking and silver burning) solidifies the silver on the surface of the device, and the silver layer has a certain adhesion to the device.

[0019] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A metallization process for a miniaturized LTCC waveguide filter, characterized in that: Including silver injection in reserved holes and silver spraying on the surface; The step of injecting silver into the reserved hole comprises: injecting silver into the reserved hole of the device so that the inner surface of the reserved hole is covered with silver paste; The surface spraying of silver comprises: after silver is injected into the reserved hole, spraying silver on the outer surface of the device.

2. The metallization process for miniaturized LTCC waveguide filter according to claim 1, characterized in that: In the step of injecting silver into the reserved holes, a dispensing machine is used to inject silver into the reserved holes of the device.

3. The metallization process for miniaturized LTCC waveguide filter according to claim 1, characterized in that: In the surface silver spraying step, silver is sprayed on the outer surface of the device using a metal spray gun.

4. The metallization process for miniaturized LTCC waveguide filter according to claim 3, characterized in that: In the surface silver spraying step, silver is sprayed on the six surfaces of the device in turn.

5. The metallization process for miniaturized LTCC waveguide filter according to claim 3, characterized in that: In the step of spraying silver on the surface, the thickness of the silver layer on the outer surface of the device is controlled by selecting the gun head model, spraying speed and spraying times of the metal spray gun.

6. The metallization process for miniaturized LTCC waveguide filter according to claim 1, characterized in that: Before silver is injected into the reserved holes, surface treatment is performed first; The surface treatment comprises: placing the device into a ball milling jar, and adding molybdenum dioxide, zirconium oxide balls and pure water; grinding the device for a certain period of time by a jar grinder, discharging the material, cleaning the material, and then ultrasonically cleaning and drying the device to obtain a smooth and clean device.

7. The metallization process for miniaturized LTCC waveguide filter according to claim 6, characterized in that: In the surface treatment step, grinding was performed by a jar grinder for 3 hours.

8. The metallization process for miniaturized LTCC waveguide filter according to claim 1, characterized in that: After the surface is sprayed with silver, silver baking and silver burning are also carried out; The silver baking and silver burning comprises: placing the device after the surface of the device is sprayed with silver into a silver baking furnace for drying, and after drying, sending the device into the silver burning furnace for silver burning.