Wafer blackening method and blackened wafer

Abstract

The invention provides a wafer blackening method, wherein the wafer comprises a lithium tantalate wafer or a lithium niobate wafer. According to the present invention, with the method, the electric conductivity of the wafer can be increased, and the blackening degree is high and uniform; and by using the method, a blackening reaction is performed in a high temperature environment without the direct contact between a reducing material and a wafer, such that the technical problems of poor blackening effect and low blackening uniformity of the lithium tantalate wafer or lithium niobate wafer canbe solved, the low transmittance can be achieved, and the transmittance is uniformly distributed.

Description

technical field [0001] The invention relates to a wafer manufacturing method, in particular to a wafer blackening method. Background technique [0002] Lithium tantalate (LiTaO3, LT) and lithium niobate (LiNbO3, LN) crystals are typical multifunctional materials with excellent piezoelectric, ferroelectric, acousto-optic and electro-optic effects, so they become surface acoustic wave (SAW) devices, Basic functional materials in the fields of optical communication, laser and optoelectronics. Widely used in the manufacture of electronic communication devices such as resonators, filters, transducers, etc., especially for the manufacture of high-frequency surface acoustic wave devices with good electromechanical coupling, temperature coefficient and other comprehensive properties, and used in mobile phones, walkie-talkies, satellite communications , aerospace and many other high-end communication fields. At present, there is no other more advantageous material to replace high-f...

AI Technical Summary

Problems solved by technology

[0006] At present, there is a Chinese patent CN200480005133.2 for the blackening of LT and LN substrates. Shin-Etsu Corporation of Japan proposes to conduct deep reduction treatment on lithium tantalate, lithium niobate and hydrogen storage metals first. The deep reduction treatment requires reducing gas or inert gas in circulation. Among them, the lithium tantalate crystal substrate to be treated is subjected to high-temperature deep reduction treatment to obtain a blackened substrate, and then the deep reduction-treated substrate is alternately stacked with the LT and LN substrates to be treated for reduction treatment. This process requires high The monovalent lithium tantalate crystal substrate is first made into a blackened clip at high temperature, and the flatness of the substrate is high, so it needs to be ground, otherwise it is difficult to ensure that the two wafers can be tightly bonded, and a second reduction treatment is required , leading to complex process, long process time and high processing cost

[0007] Chinese patent CN200410033600, Sumitomo Corporation of Japan proposes to use C, Si powder or place it in C, Si container to carry out powder embedding heat treatment on the lithium tantalate crystal in the form of raw material, and also proposes to use Ca, Al, Ti, Zn and Si metal powder The lithium tantalate crystals in the form of wafers are subjected to powder-burying heat treatment. Due to the strong reducibility of the metal element, the crystals are prone to peroxidation or destroy the piezoelectric properties of the crystals.

This kind of metal powder reduction process has certain difficulties in adjusting the proportion and uniformity control of the mixed powder, and the operation of preparing the mixed powder has a certain degree of impact on human health and work safety.

Images