Radio frequency filter and preparation method thereof
A radio frequency filter and cavity technology, applied in the filter field, can solve the problems of high process realization difficulty, high material cost, long processing flow, etc., and achieve the effect of avoiding the use of precious metal materials, simplifying the process, and improving product reliability.
Pending Publication Date: 2021-11-12
EPIC MEMS XIAMEN CO LTD
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Problems solved by technology
[0003] Whether it is a surface acoustic wave filter or a bulk acoustic wave filter, in order to maintain good radio frequency performance indicators, there are certain requirements for its working environment. It is necessary to prepare a relatively airtight cavity to isolate external water vapor, particles, There are generally two conventional methods for the impact of contamination on devices: 1. First, prepare a protective substrate, which is usually silicon, glass, ceramics, metal shells, etc., and then use wafer-level bonding, welding, adhesion, etc. The filter is isolated and protected by means of deep hole etching, physical vapor deposition and electroplating, and then processed through a series of complicated processes; the whole process is longer, the process is difficult to realize, and the cost of materials is expensive; 2. The method of covering a large area of the cavity with a film is low in cost, but the device that is sensitive to the degassing substances of the film material will affect its device performance and limit its application range
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preparation example Construction
[0055] The present invention also proposes a preparation method of a radio frequency filter, comprising:
[0056] Forming a sealed outer wall and supporting electrodes on the substrate;
[0057] depositing a sacrificial layer on the substrate formed with the sealing outer wall and the supporting electrode, and exposing the sealing outer wall and the supporting electrode;
[0058] forming a cavity shell on the surface of the sacrificial layer by using a dielectric material or a metal material;
[0059] forming support electrode openings and release holes in the cavity housing;
[0060] The sacrificial layer is etched through the release hole to form a cavity.
[0061] The preparation method of the radio frequency filter of the present invention has a simple process flow, is compatible with the semiconductor process, and greatly reduces the cost.
[0062] Further, the preparation method further includes: forming a release hole sealing layer on the release hole to seal the relea...
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Abstract
The invention provides a radio frequency filter and a preparation method thereof. The radio frequency filter comprises a base body, a sealing outer wall, a plurality of supporting electrodes and a cavity shell, wherein the supporting electrodes are arranged on the surface of the base body in a protruding mode, and the sealing outer wall is arranged on the surface of the base body in a protruding mode and surrounds the supporting electrodes. The cavity shell is positioned on the sealing outer wall and the plurality of supporting electrodes; the base body, the sealing outer wall and the cavity shell form a cavity; and the cavity shell is made of a medium and / or metal. According to the invention, a cavity shell packaging structure is formed by using a medium or a metal material, so that the influence of cured and overflowed substances of a film material on the performance of the sensitive radio frequency filter is greatly reduced.
Description
technical field [0001] The invention relates to the technical field of filters, in particular to a radio frequency filter and a preparation method thereof. Background technique [0002] With the continuous development of 5G technology, the application and demand of radio frequency filters are continuously upgraded, and the requirements for the performance indicators of radio frequency filters are constantly increasing. According to the different transmission methods of sound waves, radio frequency filters can generally be divided into: bulk acoustic wave filters and surface acoustic wave filters; among them, surface acoustic wave filters generally work below 2.5G frequency, and bulk acoustic wave filters generally work at 1.5G ~10G frequency. [0003] Whether it is a surface acoustic wave filter or a bulk acoustic wave filter, in order to maintain good radio frequency performance indicators, there are certain requirements for its working environment. It is necessary to prep...
Claims
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IPC IPC(8): H03H3/02H03H9/25H03H9/64
CPCH03H3/02H03H9/25H03H9/64
Inventor 蒋将李平王伟李林武胡念楚贾斌
Owner EPIC MEMS XIAMEN CO LTD