Preparation method of monocrystal piezoelectric film heterogeneous substrate

Abstract

The invention provides a preparation method of a monocrystal piezoelectric film heterogeneous substrate. The method comprises the following steps of: 1) providing a monocrystal piezoelectric substrate, wherein one surface of the monocrystal piezoelectric substrate is an implantation surface; 2) performing ion implantation at the implantation surface, and forming a defect layer at the preset depthof the monocrystal piezoelectric substrate; 3) providing a support substrate; 4) bonding the monocrystal piezoelectric substrate with the support substrate through a dielectric buried layer; 5) performing thinning treatment of the monocrystal piezoelectric substrate from the surface, far away from the support substrate, of the monocrystal piezoelectric substrate; and 6) stripping part of the monocrystal piezoelectric substrate along the defect layer to obtain a monocrystal piezoelectric film heterogeneous substrate comprising the support substrate, the dielectric buried layer and the monocrystal piezoelectric film which are stacked in order. The monocrystal piezoelectric substrate is thinned prior to forming of the monocrystal piezoelectric film heterogeneous substrate through stripping along the defect layer, and then stripping is performed along the defect layer to reduce the thermal mismatching between the monocrystal piezoelectric substrate and the support substrate and avoid generation of the problem of cracking caused by thermal mismatch in the stripping process.

Description

technical field [0001] The invention belongs to the technical field of substrate preparation, in particular to a method for preparing a single crystal piezoelectric thin film heterogeneous substrate. Background technique [0002] SAW (Surface Acoustic Wave) and BAW (Body Surface Wave) filters are the only solution for Sub-6GHz mobile communication filters. SAW filters combine low insertion loss and good rejection performance at low cost. However, SAW filters are generally only suitable for applications below 2GHz, and are easily affected by temperature changes (the development of TC-SAW is to solve this problem) and have low power density. BAW (FBAR) filters have excellent performance in high-frequency applications and high power density, and are suitable for very demanding high-frequency signal filtering of 4G and 5G communications. In current RF front-end systems, SAW and BAW (FBAR) filters are used in combination to achieve filtering together. [0003] In the 5G commun...

AI Technical Summary

Problems solved by technology

Existing single crystal piezoelectric thin film heterogeneous substrates generally include sequentially stacked support substrates, dielectric buried layers, and single crystal piezoelectric thin films. Since the single crystal piezoelectric substrate (such as a lithium niobate piezoelectric substrate with a thermal expansion coefficient of 15.4 or a lithium tantalate piezoelectric substrate with a thermal expansion coefficient of 16) and a supporting substrate (such as a silicon substrate with a thermal expansion coefficient of 2.5 ) has a huge difference in thermal expansion coefficient, during the process of intelligent peeling, the stress caused by thermal mismatch will cause the single crystal piezoelectric substrate and the support substrate to break

Images