Surface acoustic wave filter and manufacturing method thereof

A surface acoustic wave and manufacturing method technology, applied in the direction of impedance network, electrical components, etc., can solve the problems of increasing the manufacturing cost of surface acoustic wave devices, damaging metal electrodes or leads, and increasing wafer manufacturing costs, so as to weaken pyroelectric effect, lower temperature expansion coefficient, and improved power resistance

Pending Publication Date: 2022-07-22
GUANGDONG CANCHIP TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These increase the manufacturing cost of the wafer and further increase the manufacturing cost of the surface acoustic wave device, which is not conducive to the propagation of sound waves, and may even generate clutter or energy leakage from the substrate, resulting in deterioration of device performance
[0006] In addition, during the manufacture or use of the surface acoustic wave filter, the ambient temperature will change, because the strong pyroelectric effect of the lithium tantalate material itself will cause the electrostatic accumulation or even discharge on the surface of the lithium tantalate substrate, which will damage the metal electrode. or leads degrade device performance

Method used

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  • Surface acoustic wave filter and manufacturing method thereof
  • Surface acoustic wave filter and manufacturing method thereof
  • Surface acoustic wave filter and manufacturing method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0047] Next, the structure of the surface acoustic wave filter according to Embodiment 1 of the present invention will be described in detail.

[0048] figure 1 is a plan view obtained when the surface acoustic wave filter according to Embodiment 1 of the present invention is observed from a plan perspective, wherein, figure 1 The top view in Schematic only schematically shows a part of the SAW filter and / or resonator structure, which can be other Normal-SAW, TC-SAW, IHP-SAW filter and / or resonator structures (Note: Resonance The resonator is part of the filter, and multiple resonators can be connected by circuit to form a filter). figure 2 This is a cross-sectional view showing the surface acoustic wave filter according to Embodiment 1 of the present invention when viewed from the X-X direction.

[0049] like figure 1 As shown, the surface acoustic wave filter 1 includes a piezoelectric layer 100 and interdigital electrodes 103 formed on the piezoelectric layer 100 .

[...

Embodiment approach 2

[0066] As described above, in Embodiment 1 of the present invention, as figure 2 As shown, the above-mentioned doping structure 102 is entirely formed in the surface direction of the above-mentioned piezoelectric layer 100 .

[0067] In contrast to this, in Embodiment 2 of the present invention, such as Figure 5 As shown, the above-mentioned doping structure 102 is locally formed in the surface direction of the above-mentioned piezoelectric layer 100 .

[0068] Similarly, the piezoelectric layer 100 is doped with lithium ions or lithium oxides by ion implantation, but from the viewpoint of doping effect, the same doping effect can be obtained regardless of whether lithium ions or lithium oxides are selected.

[0069] Also, similar to the first embodiment, according to the above-described configuration of the second embodiment, it is also possible to obtain the same Figure 8 Similar performance indicators of the SAW filter 1 in the middle and low frequency bands can also b...

Embodiment approach 3

[0074] Next, in Embodiment 3, the manufacturing method of the surface acoustic wave filter according to Embodiment 1 of the present invention will be described in detail.

[0075] Image 6 It is a process sequence diagram showing the process of forming the dopant structure 102 entirely in the surface direction of the surface acoustic wave filter 1 according to Embodiment 1 of the present invention.

[0076] First, as Image 6 As shown in (a), the piezoelectric layer 100 is formed using a piezoelectric crystal composed of lithium tantalate, and then the piezoelectric crystal is prepared to be doped with lithium ions or lithium oxide by using an ion implantation technique.

[0077] Second, if Image 6 As shown in (b), lithium ions or lithium oxide are implanted by doping in the depth direction of the piezoelectric layer 100, whereby the doping structure 102 is locally formed in the depth direction of the piezoelectric layer 100, and at the same time, the piezoelectric layer 10...

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Abstract

The invention relates to a surface acoustic wave filter (1), comprising: a first substrate layer (100), which is formed from a piezoelectric crystal made of lithium tantalate and in which the piezoelectric crystal is doped with lithium ions or lithium oxide using an ion implantation technique to form a doped structure (102); the electrode layer (103) is formed on the first substrate layer (100), and the electrode layer (103) is formed on the first substrate layer (100) and is composed of an interdigital electrode; and a cover layer (104), which is formed on the electrode layer (103), and which covers the entire electrode layer (103).

Description

technical field [0001] The invention relates to a surface acoustic wave filter and a manufacturing method thereof, in particular to a surface acoustic wave filter resistant to strong pyroelectric effect and a manufacturing method thereof. Background technique [0002] Surface acoustic wave (SAW: surface acoustic wave) devices are based on the piezoelectric effect of piezoelectric materials, and are electronic devices that use surface acoustic waves on the surface of piezoelectric materials. An interdigital transducer (IDT: interdigital transducer, a periodic structure of metal electrodes shaped like hands crossing) converts electrical input signals into surface acoustic waves. With the rapid development of information technology, surface acoustic wave filters are widely used in lithium tantalate (LiTaO 3 ) to form, and used in various communication equipment, data transmission equipment, audio-visual equipment and positioning and navigation equipment. In particular, the in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03H9/64H03H9/02H03H3/08H03H3/10
CPCH03H9/6489H03H9/02559H03H9/02574H03H9/02921H03H9/02834H03H9/02818H03H3/08H03H3/10
Inventor 许欣
Owner GUANGDONG CANCHIP TECH CO LTD
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