CN1281548C - Tech of sintering Nb2O5-TiO2 system deelectric ceramic - Google Patents

Abstract

The present invention belongs to the preparing field of dielectric ceramic. The existing art has the problems of long preparing cycle, low efficiency, high energy consumption, small dielectric coefficient and little industrial manufacture selectivity, and is not favorable to the industrial manufacture practicality. The present invention provides a sintering process for dielectric Nb2O5-TiO2 system ceramic, which comprises the steps that Nb2O5 and TiO2 powdery row materials are furnished according to the proportion of (Nb2O5) <1-x>(TiO2) <x>, the x is in the range of 0.01 to 0.13, the temperature is raised to 1250 DEG C in the heating rate of 200 DEG C/ hour, heat preservation is carried out for 18 hours, polyvinyl alcohol (PVA) adhesive is mixed in the powdery row materials which are presintered to make granules, the mass concentration of the polyvinyl alcohol (PVA) adhesive is 3 percent, wherein the weigh of the adhesive is 6 percent of the total weight of the powdery row materials; the powdery row materials are pressed into blank body sheets under the pressure of 200MPa, the temperature is raised to 1350 DEG C to 1380 DEG C in the heating rate of 100 DEG C/ hour, the heat preservation is carried out for two to 15 hours, then the temperature is reduced to room temperature in the rate of 150 DEG C/ hour, and finally, compact sheet-shaped ceramic bodies are sintered and prepared. The present invention has the advantages of short preparing cycle, low energy consumption, large dielectric coefficient and multiple industrial application selectivity.

Description

Nb 2O 5-TiO 2System dielectric ceramic sintering process

Technical field

The invention belongs to the dielectric ceramic preparation field.

Background technology

Along with the development of electronics technology, the size of microelectronic circuits is done more and more forr a short time, so also more and more higher to the mini component performance demands.Concerning capacitance component, dielectric properties has limited it and has minimized degree.Modern electronic material will no longer can satisfy the performance requriements of capacitance component in the microelectronic circuits.For example: the capacitor dielectric layer in the dynamic RAM (Dynamic Random Access Memory is called for short DRAM) is to use SiO ₂Or Si ₃N ₄Make, at routine measurement condition (1MHz frequency with 25 ℃) their relative dielectric coefficient ε down _rBe respectively 3.8 and 6.0, this can not satisfy the demand of current increasing storage capacity far away.Want the DRAM of the above storage capacity of development and production 1G, seek a kind of high-dielectric coefficient, the type material of low-dielectric loss has become the task of top priority.

Because Nb ₂O ₅With the semiconductor technology compatibility, through the Nb of doping vario-property ₂O ₅Dielectric coefficient can reach more than 100 relatively, thereby becomes the preferred material of DRAM.Research Nb ₂O ₅The method of doping vario-property is earlier with adulterated Nb ₂O ₅Be prepared into pottery, find out the doping ratio and the preparation technology that make its dielectric properties reach optimum, again it is developed into the dielectric film with actual application value, so just can make it become the type material of high-performance topographically elevated microelectronic capacitor spare of future generation.

At present, there have been some research groups being engaged in the research work of this respect in the world.For example: 1996 the 11st volumes of article 1:Journal of Materials Research (" investigation of materials journal " magazine) are entitled as " Dielectric properties of TiO ₂-Nb ₂O ₅Crystallographic shear structures " (" TiO ₂-Nb ₂O ₅The Dielectric Properties of crystallographic shear structure ").Article is pointed out: at Nb ₂O ₅Middle a spot of TiO that mixes ₂, can increase substantially its dielectric coefficient.Pure Nb ₂O ₅Relative dielectric coefficient be 29.9 under the routine measurement condition; Doping 7.7mol%, 28.6mol% and 50mol%TiO ₂Nb ₂O ₅The relative dielectric coefficient of pottery is respectively 82,129 and 101.2002 the 54th volumes of article 2:MaterialsLetters (" material wall bulletin " magazine) are entitled as " Dielectric behaviors ofNb ₂O ₅(0.95): 0.05TiO ₂Ceramic and single crystal " (" doping 5mol%TiO ₂Nb ₂O ₅Pottery and monocrystalline Dielectric Properties "), studied doping 5mol%TiO ₂Nb ₂O ₅The dielectric properties of pottery and monocrystalline.The relative dielectric coefficient of its pottery is 175, and loss is 0.10.

But their research work exists following problems:

Article 1:1. is for (Nb ₂O ₅) _1-x(TiO ₂) _xPreparation technology's preparation cycle of system pottery is long partially, and energy consumption is bigger than normal, is unfavorable for industrial production practicability.The secondary pre-burning that they adopt (earlier at 1300 ℃, once more at 1350 ℃) complex process, temperature drift, the time is grown (round the clock several) partially; Sintering time is grown (16-24 hour) partially; Oxygen annealing technology (1100 ℃ of insulations 2 hours, dropping to 500 ℃ from 1100 ℃ in 8 hours then) time is long, complex process;

2. studies show that: Nb ₂O ₅-TiO ₂The system pottery is along with the doping content difference, and its dielectric properties are significantly different.Doping 8mol%, 28mol% and 50mol%TiO only studied in article 1 ₂The system pottery of 3 components, and the highest relative dielectric coefficient is also less than 130.Therefore, the selection space of the development of high-dielectric coefficient device and production practicability is very little;

Article 2: pre-burning and be sintered to 1300 ℃ among the preparation technology, 24 hours and 1400 ℃, 24 hours.Pre-burning and sintering temperature are higher, and soaking time is long partially, and dielectric coefficient is lower, and have only studied the sintering process of 5%mol doping content, exist preparation cycle long too, efficient is low, and energy consumption is big, dielectric coefficient is little, and the industrial production selectivity is few, is unfavorable for the problem of industrial production practicability.

Summary of the invention

A kind of preparation cycle is short, energy consumption is low and make (Nb ₂O ₅) _1-x(TiO ₂) _xThe dielectric coefficient of system pottery various ingredients (X=0.01～0.13) is greater than 120 sintering process.

The invention provides a kind of Nb ₂O ₅-TiO ₂System dielectric ceramic sintering process is characterized in that, may further comprise the steps:

1) batching: in X=0.01～0.13 scope with Nb ₂O ₅And TiO ₂Powder is by proportioning (Nb ₂O ₅) _1-x(TiO ₂) _xPrepare burden mechanical ball milling 12 hours, oven dry;

2) pre-burning: be warming up to 1250 ℃ with 200 ℃/hour temperature rise rates, be incubated 18 hours.Again with the powder mechanical ball milling after the pre-burning 12 hours, oven dry;

3) granulating and forming: polyvinyl alcohol (PVA) glue that will mix 3% mass concentration in the powder after pre-burning carries out granulation, and wherein the weight of glue is 6% of powder gross weight; Under 200MPa pressure, be pressed into the base substrate sheet;

4) sintering: be warming up to 1350 ℃～1380 ℃ with 100 ℃/hour temperature rise rates, and be incubated 2～15 hours, reduce to room temperature with 150 ℃/hour speed then, finally sinter fine and close flaky pottery body into.

Compare with existing processes, the clear superiority of this technology is:

(1) only with a pre-burning, calcined temperature is reduced to 1250 ℃, only is incubated 18 hours; Sintering temperature is reduced to 1350 ℃～1380 ℃, only is incubated 2～15 hours; Do not need to anneal with oxygen atmosphere.Preparation cycle obviously shortens, and production efficiency improves greatly, therefore prepares required energy consumption and reduces significantly, very helps following industrial production practicability;

(2) at TiO ₂In doping volumetric molar concentration X=0.01～0.13 scope, the dielectric coefficient of each component of this technology all is greatly improved, and reaches more than 120, is present Nb ₂O ₅-TiO ₂System ceramic dielectric coefficient highest level.Compare with article 2 technologies as the ceramic dielectric coefficient of X=0.05 component and to have improved 30%; The ceramic dielectric coefficient of X=0.08 component and comparing of article 1 technology are 2 times of the latter under this technology;

(3) at TiO ₂In doping volumetric molar concentration X=0.01～0.13 scope, the dielectric coefficient of this technology all components is all greater than 120, for the development and the production practicability of high-dielectric coefficient device in the future provides very big selection space.

Embodiment

Embodiment one: with Nb ₂O ₅And TiO ₂Powder is by proportioning (Nb ₂O ₅) _0.95(TiO ₂) _0.05Prepare burden mechanical ball milling 12 hours, oven dry; Be warming up to 1250 ℃ of pre-burnings with 200 ℃/hour speed, be incubated 18 hours.Again with the powder mechanical ball milling after the pre-burning 12 hours, oven dry; Polyvinyl alcohol (PVA) glue that will mix 3% mass concentration in the powder after pre-burning carries out granulation, and wherein the weight of glue is 6% of powder gross weight; Under 200MPa pressure, be pressed into the base substrate sheet; Base substrate is warming up to 1380 ℃ of sintering with 100 ℃/hour speed, and is incubated 2 hours, reduce to room temperature with 150 ℃/hour speed then, finally sinter fine and close flaky pottery body into; At ceramic plate upper and lower surface spraying plating gold electrode, measure its dielectric properties with HP4284ALCR precision measuring instrument (1MHz frequency and 25 ℃) under the routine measurement condition.

Measuring result sees Table 1.

Embodiment two: with Nb ₂O ₅And TiO ₂Powder is by proportioning (Nb ₂O ₅) 0.92 (TiO ₂) 0.08 prepare burden mechanical ball milling 12 hours, oven dry; Be warming up to 1250 ℃ of pre-burnings with 200 ℃/hour speed, be incubated 18 hours.Again with the powder mechanical ball milling after the pre-burning 12 hours, oven dry; Polyvinyl alcohol (PVA) glue that will mix 3% mass concentration in the powder after pre-burning carries out granulation, and wherein the weight of glue is 6% of powder gross weight; Under 200MPa pressure, be pressed into the base substrate sheet; Base substrate is warming up to 1370 ℃ of sintering with 100 ℃/hour speed, and is incubated 15 hours, reduce to room temperature with 150 ℃/hour speed then, finally sinter fine and close flaky pottery body into; At ceramic plate upper and lower surface spraying plating gold electrode, measure its dielectric properties with HP4284ALCR precision measuring instrument (1MHz frequency and 25 ℃) under the routine measurement condition.Measuring result sees Table 1.

(Nb under table 1 different process ₂O ₅) _1-x(TiO ₂) _xSystem ceramic dielectric performance

Component x (mol%)		0.01	0.03	0.05	0.07	0.08	0.09	0.11	0.13
										This technology	ε r	125	133	217	153	155	170	141	145
tanδ	0.053	0.067	0.078	0.227	0.226	0.248	0.223	0.198
									Non-technology		ε r	/	/	175 [1]	/	82 [2]	/	/	/
tanδ	/	/	0.10 [1]	/	0.15 [2]	/	/	/

Annotate: [1] is the dielectric properties under article 2 technologies;

[2] be dielectric properties under article 1 technology.

Claims (1)

1, a kind of Nb ₂O ₅-TiO ₂System dielectric ceramic sintering process is characterized in that, may further comprise the steps:

1) batching: in X=0.01～0.13 scope with Nb ₂O ₅And TiO ₂Powder is by proportioning (Nb ₂O ₅) _1-x(TiO ₂) _xPrepare burden mechanical ball milling 12 hours, oven dry;

2) pre-burning: be warming up to 1250 ℃ with 200 ℃/hour temperature rise rates, be incubated 18 hours; Again with the powder mechanical ball milling after the pre-burning 12 hours, oven dry;

3) granulating and forming: the polyvinyl alcohol glue that mixes 3% mass concentration in the powder after pre-burning carries out granulation, and wherein the weight of glue is 6% of powder gross weight; Under 200MPa pressure, be pressed into the base substrate sheet;

4) sintering: be warming up to 1350 ℃～1380 ℃ with 100 ℃/hour temperature rise rates, and be incubated 2～15 hours, reduce to room temperature with 150 ℃/hour speed then, finally sinter fine and close flaky pottery body into.