Blackening method for lithium tantalate or lithium niobate crystal substrate

A technology of lithium niobate and lithium tantalate, which is applied in chemical instruments and methods, crystal growth, post-processing details, etc., can solve problems such as high flatness requirements, difficulty in ensuring tight bonding of wafers, and low process efficiency

Active Publication Date: 2016-10-26
TDG HLDG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Japanese patent JP2004-002853 proposes to perform deep reduction treatment on condensed matter such as LT wafers, LT polycrystalline ceramics, and hydrogen storage materials in a reducing atmosphere or an inert atmosphere at a temperature higher than the Curie temperature (700 ° C ~ 1200 ° C), and then reduce the depth The reduced condensed LT wafer and the LT substrate to be processed are overlapped and placed in a reducing atmosphere such as vacuum or hydrogen for blackening treatment. This technology requires wafer grinding and has high requirements for flatness. It is difficult to ensure that the two wafers Tight fit, low process efficiency and high manufacturing cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Firstly, organic silica gel, lithium carbonate powder, and Zn powder are mixed according to the ratio of 1:1:0.1, and then coated on the lithium tantalate or lithium niobate crystal substrate to be blackened by screen printing, and placed in a stainless steel container Then place the stainless steel container in a heat treatment furnace, heat it up to 460°C for 6 hours under a nitrogen atmosphere with a flow rate of 6L / min, and then cool it down to room temperature to take out the wafer. Next, the wafer at room temperature was placed on a heating plate at 80° C. for a thermal cycle test. As a result, the surface potential generated at the instant when the substrate was placed on the heating plate was 500 V or less, and no spark phenomenon was observed on the substrate surface. The volume resistivity is about 10 12 About Ω·cm, no unevenness in hue was observed visually.

Embodiment 2

[0028] First, mix organic silica gel, lithium carbonate powder, and Zn powder in a ratio of 1:1:0.2, and then coat it on the lithium tantalate or lithium niobate crystal substrate to be blackened by screen printing, and place it in a stainless steel container Then place the stainless steel container in a heat treatment furnace, heat it up to 460°C for 6 hours under a nitrogen atmosphere with a flow rate of 6L / min, and then cool it down to room temperature to take out the wafer. Next, the wafer at room temperature was placed on a heating plate at 80° C. for a thermal cycle test. As a result, the surface potential generated at the instant when the substrate was placed on the heating plate was 500 V or less, and no spark phenomenon was observed on the substrate surface. The volume resistivity is about 10 11 About Ω·cm, no unevenness in hue was observed visually.

Embodiment 3

[0030] First, mix organic silica gel, lithium carbonate powder, and Zn powder in a ratio of 1:1:0.3, and then coat it on the lithium tantalate or lithium niobate crystal substrate to be blackened by screen printing, and place it in a stainless steel container Then place the stainless steel container in a heat treatment furnace, heat it up to 460°C for 6 hours under a nitrogen atmosphere with a flow rate of 7L / min, and then cool it down to room temperature to take out the wafer. Next, the wafer at room temperature was placed on a heating plate at 80° C. for a thermal cycle test. As a result, the surface potential generated at the moment when the substrate was placed on the heating plate was 300 V or less, and no spark phenomenon was observed on the substrate surface. The volume resistivity is about 10 10 About Ω·cm, no unevenness in hue was observed visually.

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PUM

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Abstract

The invention relates to a blackening method for a lithium tantalate or lithium niobate crystal substrate. The method comprises the following steps: preparing a mixed system from an elemental material with deoxidation ability and a mixture of a glue and a certain proportion of lithium carbonate powder; uniformly coating both sides of a to-be-treated lithium tantalate or lithium niobate crystal substrate by using a screen printing method; and placing the substrate in a stainless steel container, then putting the container into a heat treatment furnace, and carrying out reduction treatment on the to-be-treated lithium tantalate or lithium niobate crystal substrate in a nitrogen atmosphere with a flow of 6 L/min to 10 L/min under and at a temperature below the Curie temperature of the to-be-treated lithium tantalate or niobate crystal substrate. In the mixed system, organic silicone glue is used as glue; and the elemental material with deoxidation ability is Zn powder which accounts for 35% or less of the mass of the mixed system. According to the invention, reduced blackening treatment of the lithium tantalate or lithium niobate crystal substrate is carried out under Curie temperature conditions; and through blackening treatment, the pyroelectric properties of the substrate is reduced, and thus, manufacturing cost for a SAW filter is lowered and the production efficiency of the SAW filter is improved.

Description

technical field [0001] The invention relates to crystal materials, in particular to a blackening treatment method for lithium tantalate or lithium niobate crystal substrates. Background technique [0002] Lithium tantalate (LiTaO3, LT) and lithium niobate (LiNbO3, LN) crystals are multifunctional crystals integrating piezoelectric, ferroelectric, pyroelectric, nonlinear, electro-optical, photoelastic, photorefractive and other functions. material with good thermal and chemical stability. At present, it has been widely used in the fields of surface acoustic wave devices, optical communications, lasers and optoelectronics. Especially as a piezoelectric wafer material, the substrate produced by annealing, polarization, orientation, cutting, spheronizing, reference plane, multi-wire cutting, grinding, polishing and other processes has excellent piezoelectric properties and can be polished on the mirror surface. Fabricate Surface Acoustic Wave (SAW) and Bulk Wave (BAW) devices ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B33/12
CPCC30B33/12
Inventor 姚志炎沈浩归欢焕朱海瀛顾潇威
Owner TDG HLDG CO LTD
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