CN117088678A - Preparation method of rare earth doped IZO target - Google Patents

Abstract

The invention relates to the technical field of target materials, and specifically relates to a rare earth doped IZO target material and a preparation method thereof. The preparation method includes the steps of raw material selection, primary ball milling, secondary ball milling, spray granulation, press molding and high-temperature sintering. The present invention uses a variety of rare earth doping process methods, and simultaneously optimizes the weight ratio of raw materials, the amount of deionized water used, the solid content, the particle size and density of the powder, and the reasonable high-temperature sintering process to obtain high relative density and Large size rare earth doped IZO target with small grain size. The large-size rare earth-doped IZO target prepared by the preparation method provided by the invention is suitable for the preparation of modern electronic components and has broad application prospects.

Description

A kind of preparation method of rare earth doped IZO target material

Technical field

The present invention relates to the technical field of target materials, and in particular to a method for preparing a rare earth-doped IZO target material.

Background technique

In recent years, flat panel display technologies such as liquid crystal displays (LCDs), active organic light-emitting diode displays (AMOLEDs), and flexible displays have developed rapidly. The importance of thin-film transistors (TFTs) as core components is self-evident. Among them, TFTs based on oxide semiconductors have attracted widespread attention from academia and industry due to their advantages such as high carrier concentration, good electrical uniformity, high visible light transmittance, and low cost. The performance of the semiconductor layer in TFT largely determines the performance of the entire device. Among oxide semiconductors, indium zinc oxide (In ₂ O ₃ -ZnO, IZO) semiconductor has high carrier mobility and large forbidden area. The tape width (>3ev) can meet display requirements such as large size, high resolution, and high aperture ratio, and has great application potential.

The IZO targets currently on the market have the following problems: 1. Large-size IZO planar targets are difficult to sinter and have large warpage (size area > 1800cm ² ). 2. The relative density is low and the grain size is large, which affects the coating performance and carrier mobility. 3. The sintering temperature is as high as 1450-1500℃ and the sintering time is long. Chinese invention patent CN115925410B discloses a praseodymium-doped indium zinc oxide sputtering target and its preparation method, and obtains a praseodymium-doped indium zinc oxide sputtering target with fine grains and controllable secondary phases. However, the patent does not involve the technical content of adding manganese trioxide powder as a burning aid to improve the warpage of large-size IZO planar targets.

Contents of the invention

In view of this, the purpose of the present invention is to propose a method for preparing rare earth-doped IZO targets to solve the problem of large sintering warpage of existing large-size IZO planar targets, which affects target processing and utilization.

Based on the above purpose, the present invention provides a preparation method of rare earth doped IZO target material, including the following steps:

(1) Raw material selection: The raw materials include the following components in parts by weight: 90 parts of indium oxide powder, 6-10 parts of zinc oxide powder, 0.01-2 parts of praseodymium oxide powder, 0.01-2 parts of manganese trioxide powder, among which, The BET of indium oxide powder is 10-12m ² /g, the BET of zinc oxide powder is 30-40m ² /g, the BET of praseodymium oxide powder is 2.5-4m ² /g, and the BET of manganese trioxide powder is 11-13m ² /g;

(2) One-time ball milling: Add deionized water and zinc oxide powder to a ball milling tank equipped with φ1-2mm zirconium beads, and stir for 16-24 hours to obtain zinc oxide slurry;

(3) Secondary ball milling: Add deionized water to the zinc oxide slurry, then pour indium oxide powder, praseodymium oxide powder, and manganese trioxide powder together for ball milling. The ball milling time is 24-48h to obtain rare earth doped IZO. slurry;

(4) Spray granulation: Granulate the rare earth-doped IZO slurry in a dryer, set the inlet air temperature to 200-230°C and the outlet air temperature to 80-110°C to obtain rare earth-doped IZO powder;

(5) Press molding: Put the rare earth-doped IZO powder into a mold and perform isostatic pressing at a molding pressure of 300-400Mpa to obtain a rare earth-doped IZO embryo with an area ≥ 1800 cm ² and a thickness ≥ 0.6 cm;

(6) High-temperature sintering: Put the rare earth-doped IZO embryo into a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering. The sintering temperature is 1400-1450°C to obtain a rare earth-doped IZO target.

Preferably, the weight of deionized water in step (2) is equal to the weight of zinc oxide powder.

Preferably, the solid content of the rare earth-doped IZO slurry in step (3) is 35%-50%.

Preferably, the particle size D50 of the rare earth-doped IZO powder in step (4) is 35-50um, the bulk density is ≥1.2g/cm ³ , and the tap density is ≥1.4g/cm ³ .

Preferably, the length of the rare earth-doped IZO embryo in step (5) is 1.5m, the width is 1m, and the thickness is 0.015m.

Preferably, the specific steps of sintering in step (6) are:

S1: 0℃ to 600℃, heating for 40-60h;

S2: Insulation at 600℃ for 5-10h;

S3: 600℃ to 1200-1300℃, heating for 20-40h;

S4: 1200-1300℃ insulation for 10-20h;

S5: 1200-1300℃ to 1400-1450℃, heating for 20-40h;

S6: 1400-1450℃ insulation for 20-30h;

S7: 1400-1450℃ drop to 30℃, cool down for 20-30h.

Preferably, it is characterized in that the relative density of the rare earth-doped IZO target material in step (6) is 99.3%-99.7%, and the grain size is 3-5um.

Beneficial effects of the present invention:

Reasonable selection of raw materials: Indium oxide powder, zinc oxide powder, and manganese trioxide powder with higher specific surface area are selected as raw materials to further refine the grains and improve the density.

Application of spray granulation: Drying and granulating rare earth-doped IZO slurry can obtain powder with good sphericity, making the subsequent molding process smoother.

Optimization of high-temperature sintering process: The addition of manganese trioxide powder plays a role in assisting sintering and fusion. Combined with a reasonable sintering process, including multi-stage heating, cooling and heat preservation steps, the grains can be better grown and the target can be heated and shrunk evenly, thereby obtaining a large-sized rare earth-doped IZO target with good flatness.

Low sintering temperature: By controlling the specific surface area of the powder in the raw material, the powder activity is improved, the sintering temperature of the target material is reduced, and the cost is reduced.

Generally speaking, the preparation method of the present invention can obtain large-sized rare earth doped IZO targets with high relative density, small grain size, low sintering temperature and good flatness, which can meet the requirements for the preparation of modern electronic components and has broad prospects. Application prospects.

Description of the drawings

In order to explain the present invention or technical solutions in the prior art more clearly, the drawings required for the embodiments will be briefly introduced below.

Figure 1 is an SEM picture of rare earth doped IZO powder in Example 1 of the present invention;

Figure 2 is a grain diagram of the rare earth doped IZO target in Example 1 of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to specific embodiments.

Example 1

A method for preparing rare earth doped IZO targets, including the following steps:

(1) Raw material selection: The BET of indium oxide powder is 11.4m ² /g, the BET of zinc oxide powder is 35.6m ² /g, the BET of praseodymium oxide powder is 2.6m ² /g, and the BET of manganese trioxide powder is 11.2m ² /g;

(2) One-time ball milling: Add 8g deionized water and 8g zinc oxide powder into a ball milling tank equipped with φ2mm zirconium beads, and stir for 16 hours to obtain zinc oxide slurry;

(3) Secondary ball milling: Add deionized water to the zinc oxide slurry, then pour 90g of indium oxide powder, 0.01g of praseodymium oxide powder, and 0.01g of manganese trioxide powder together for ball milling. The ball milling time is 24 hours to obtain a solid. Rare earth doped IZO slurry with a content of 48.3%;

(4) Spray granulation: Granulate the rare earth doped IZO slurry in a dryer, set the inlet air temperature to 230°C and the outlet air temperature to 110°C to obtain rare earth doped IZO powder. The particle size of the rare earth doped IZO powder is D50 = 48.6um, bulk density = 1.47g/cm ³ , tap density = 1.78g/cm ³ ;

(5) Press molding: Put the rare earth-doped IZO powder into a mold and perform isostatic pressing at a molding pressure of 300Mpa to obtain a rare earth-doped IZO embryo with an area of 2000cm ² and a thickness of 0.8cm;

(6) High-temperature sintering: Put the rare earth-doped IZO embryo into a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering. Raise the temperature from 0°C to 600°C for 40 hours; keep it at 600°C for 10 hours; raise the temperature from 600°C to 1300°C and raise the temperature for 40 hours. ; 1300°C for 10 hours: 1300°C to 1450°C, heating for 40 hours; 1450°C for 20 hours; 1450°C to 30°C, and 30 hours of cooling to obtain a rare earth-doped IZO target.

Example 2

A method for preparing rare earth doped IZO targets, including the following steps:

(1) Raw material selection: The BET of indium oxide powder is 11.4m ² /g, the BET of zinc oxide powder is 35.6m ² /g, the BET of praseodymium oxide powder is 3.2m ² /g, and the BET of manganese trioxide powder is 12.1m ² /g;

(2) One-time ball milling: Add 8g deionized water and 8g zinc oxide powder into a ball milling tank equipped with φ2mm zirconium beads, and stir for 22 hours to obtain zinc oxide slurry;

(3) Secondary ball milling: Add deionized water to the zinc oxide slurry, then pour 90g of indium oxide powder, 1g of praseodymium oxide powder, and 1g of manganese trioxide powder together for ball milling. The ball milling time is 35h, and the solid content is obtained. 40% rare earth doped IZO slurry;

(4) Spray granulation: Granulate the rare earth doped IZO slurry in a dryer, set the inlet air temperature to 210°C and the outlet air temperature to 100°C to obtain rare earth doped IZO powder. The particle size of the rare earth doped IZO powder is D50 = 42.3um, bulk density = 1.36g/cm ³ , tap density = 1.63g/cm ³ ;

(5) Press molding: Put the rare earth-doped IZO powder into a mold and perform isostatic pressing at a molding pressure of 350Mpa to obtain a rare earth-doped IZO embryo with an area of 2000cm ² and a thickness of 0.8cm;

(6) High-temperature sintering: Put the rare earth-doped IZO embryo into a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering. Raise the temperature from 0°C to 600°C for 50 hours; keep it at 600°C for 8 hours; raise the temperature from 600°C to 1250°C and raise the temperature for 30 hours. ; Keep 1250℃ for 15h; 1250℃ rise to 1420℃, raise the temperature for 30h; keep 1420℃ for 25h; 1420℃ drop to 30℃, cool down for 25h, to obtain the rare earth doped IZO target.

Example 3

A method for preparing a rare earth doped IZO target material, including the following steps:

(1) Raw material selection: The BET of indium oxide powder is 11.4m ² /g, the BET of zinc oxide powder is 35.6m ² /g, the BET of praseodymium oxide powder is 3.9m ² /g, and the BET of manganese trioxide powder is 12.8m ² /g;

(2) One-time ball milling: Add 8g deionized water and 8g zinc oxide powder into a ball milling tank equipped with φ2mm zirconium beads, and stir for 24 hours to obtain zinc oxide slurry;

(3) Secondary ball milling: Add deionized water to the zinc oxide slurry, then pour 90g of indium oxide powder, 2g of praseodymium oxide powder, and 2g of manganese trioxide powder together for ball milling. The ball milling time is 48h, and the solid content is obtained. 35.6% rare earth doped IZO slurry;

(4) Spray granulation: Granulate the rare earth doped IZO slurry in a dryer, set the inlet air temperature to 200°C and the outlet air temperature to 80°C to obtain rare earth doped IZO powder. The particle size of the rare earth doped IZO powder is D50 = 36.8um, bulk density = 1.25g/cm ³ , tap density = 1.42g/cm ³ ;

(5) Press molding: Put the rare earth-doped IZO powder into a mold and perform isostatic pressing at a molding pressure of 400Mpa to obtain a rare earth-doped IZO embryo with an area of 2000cm ² and a thickness of 0.8cm;

(6) High-temperature sintering: Put the rare earth-doped IZO embryo into a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering. Raise the temperature from 0°C to 600°C for 60 hours; maintain the temperature at 600°C for 5 hours; raise the temperature from 600°C to 1200°C and raise the temperature for 20 hours. ; 1200℃ for 10h: 1200℃ to 1400℃, heating for 20h; 1400℃ for 20h; 1400℃ to 30℃, cooling for 20h to obtain rare earth doped IZO target.

Comparative example 1

The difference from Example 2 is that the BET of praseodymium oxide powder is 1.2m ² /g.

Comparative example 2

The difference from Example 2 is that the BET of dimanganese trioxide powder is 3.5 m ² /g.

Comparative example 3

The difference from Example 2 is that no manganese trioxide powder is added to the raw materials.

Comparative example 4

The difference from Example 2 is that the added amount of manganese trioxide powder is 4g.

Performance test: The relative density, grain size, and warpage of the target materials prepared in Examples 1-3 and Comparative Examples 1-4 were tested respectively. The results are shown in the table.

Table 1 Examples 1-3, performance test results of Comparative Examples 1-4

Data analysis: It can be seen from Examples 1-3 that the rare earth doped IZO target prepared by the present invention has higher relative density, lower grain size and better warpage. Adding different proportions of manganese trioxide powder can effectively improve the overall performance of the target and reduce the sintering temperature of the target. It can be seen from Example 2 and Comparative Examples 1-2 that the specific surface area of manganese trioxide powder The specific surface area of praseodymium oxide powder and praseodymium oxide powder have a certain impact on the comprehensive performance of the target material. Among them, the high specific surface area of manganese trioxide powder helps to reduce the warpage of the target material. It can be seen from Example 2 and Comparative Examples 3-4 It is found that when manganese trioxide powder is not added, the overall performance of the target material is relatively low, and excessive addition of manganese trioxide powder is not conducive to the overall performance of the target material.

It can be seen from Figure 1 that the rare earth-doped IZO powder involved in the target preparation process of the present invention has good sphericity, which helps to improve the overall performance of the target. It can be seen from Figure 2 that the rare earth-doped IZO powder prepared by the present invention The rare earth doped IZO target has high density.

Those of ordinary skill in the art should understand that the discussion of any above embodiments is only illustrative, and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples; under the spirit of the present invention, the above embodiments or Combinations between technical features in different embodiments are also possible, steps can be implemented in any order, and there are many other variations of different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

The invention is intended to cover all such alternatives, modifications and variations falling within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (7)

1. The preparation method of the rare earth doped IZO target is characterized by comprising the following steps of:

(1) Raw material selection: the raw materials comprise the following components in parts by weight: 90 parts of indium oxide powder, 6-10 parts of zinc oxide powder, 0.01-2 parts of praseodymium oxide powder and 0.01-2 parts of manganese sesquioxide powder, wherein the BET of the indium oxide powder is 10-12m ² Per g, the BET of the zinc oxide powder is 30-40m ² Per g, BET 2.5-4m of praseodymium oxide powder ² Manganese sesquioxide powder BET of 11-13 m/g ² /g；

(2) Ball milling for the first time: adding deionized water and zinc oxide powder into a ball milling tank filled with zirconium beads with phi 1-2mm, and stirring for 16-24 hours to obtain zinc oxide slurry;

(3) Secondary ball milling: adding deionized water into zinc oxide slurry, and then pouring indium oxide powder, praseodymium oxide powder and manganese sesquioxide powder into the slurry for ball milling for 24-48 hours to obtain rare earth doped IZO slurry;

(4) And (3) spray granulation: granulating the rare earth doped IZO slurry by a dryer, setting the air inlet temperature to be 200-230 ℃ and the air outlet temperature to be 80-110 ℃ to obtain rare earth doped IZO powder;

(5) And (5) press forming: filling rare earth doped IZO powder into a mold, and performing isostatic compaction under 300-400Mpa to obtain powder with area not less than 1800cm ² Rare earth doped IZO blank with the thickness more than or equal to 0.6 cm;

(6) High-temperature sintering: and (3) putting the rare earth doped IZO green body into a high-temperature sintering furnace with normal pressure oxygen atmosphere for sintering at 1400-1450 ℃ to obtain the rare earth doped IZO target.

2. The method of preparing a rare earth doped IZO target according to claim 1, wherein the weight of deionized water in the step (2) is equal to the weight of zinc oxide powder.

3. The method for preparing a rare earth doped IZO target according to claim 1, wherein the solid content of the rare earth doped IZO slurry in the step (3) is 35% -50%.

4. The method for producing a rare earth doped IZO target according to claim 1, wherein the rare earth doped IZO powder in the step (4) has a particle diameter D50=35-50. Mu.m, and a bulk density of 1.2g/cm or more ³ The tap density is more than or equal to 1.4g/cm ³ 。

5. The method for producing a rare earth doped IZO target according to claim 1, wherein the area of the rare earth doped IZO blank in the step (5) is 2000cm ² The thickness was 0.8cm.

6. The method for preparing a rare earth doped IZO target according to claim 1, wherein the specific step of sintering in the step (6) is:

s1: raising the temperature to 600 ℃ from 0 ℃ and raising the temperature for 40-60h;

s2: preserving heat for 5-10h at 600 ℃;

s3: heating to 600-1200 deg.C for 20-40 hr;

s4: preserving heat for 10-20h at 1200-1300 ℃;

s5: raising the temperature to 1400-1450 ℃ at 1200-1300 ℃ for 20-40h;

s6: preserving heat for 20-30h at 1400-1450 ℃;

s7: cooling 1400-1450 deg.C to 30 deg.C, and cooling for 20-30 hr.

7. The method of preparing a rare earth doped IZO target according to claim 1, wherein the rare earth doped IZO target in step (6) has a relative density of 99.3% -99.7% and a grain size of 3-5um.