Preparation Method of Single Crystal Piezoelectric Thin Film Heterogeneous Substrate

Abstract

The invention provides a method for preparing a heterogeneous substrate of a single crystal piezoelectric thin film, comprising the following steps: 1) providing a single crystal piezoelectric substrate, one surface of the single crystal piezoelectric substrate is the injection surface; 2) injecting Perform ion implantation on the single crystal piezoelectric substrate to form a defect layer at a preset depth; 3) Provide a supporting substrate; 4) Bond the single crystal piezoelectric substrate to the supporting substrate through a dielectric buried layer; 5 ) Thinning the single crystal piezoelectric substrate from the surface of the single crystal piezoelectric substrate away from the support substrate; 6) Peeling off part of the single crystal piezoelectric substrate along the defect layer to obtain a support substrate including sequentially stacked , dielectric buried layer and single crystal piezoelectric thin film heterogeneous substrate. The present invention first thins the single crystal piezoelectric substrate before peeling off along the defect layer to form a single crystal piezoelectric thin film heterogeneous substrate, and then peels off along the defect layer, which can reduce the distance between the single crystal piezoelectric substrate and the supporting substrate The thermal mismatch problem avoids the split problem caused by thermal mismatch during the peeling 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

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