Zinc magnesium oxide target material and preparation method thereof

Abstract

The invention belongs to the technical field of sputtering target materials, and discloses a preparation method of a zinc magnesium oxide target material, which comprises the following steps: mixing zinc oxide powder and magnesium oxide powder to obtain mixed powder; the mixed powder is put into a mold for cold isostatic pressing, pre-sintering and crushing, and pre-sintered powder is obtained; putting the pre-sintered powder into a stainless steel sheath, carrying out hot isostatic pressing sintering, cooling to normal temperature and normal pressure, and polishing to obtain a zinc magnesium oxide target material; wherein the presintering temperature ranges from 800 DEG C to 900 DEG C, and the presintering time ranges from 30 min to 50 min; in addition, the invention further discloses the zinc magnesium oxide target material, the raw material powder of the zinc magnesium oxide target material is pre-sintered, the smoothness of the surface of the zinc magnesium oxide target material is improved, and therefore the utilization rate of the material is improved.

Description

Technical Field

[0001] The present application relates to the technical field of sputtering target materials, and in particular to a zinc magnesium oxide target material and a preparation method thereof. Background Art

[0002] Zinc magnesium oxide (ZnMgO) target is a key material for thin film deposition and surface coating. It is usually composed of a mixture of zinc oxide (ZnO) and magnesium oxide (MgO) and has excellent optical and electrical properties. This target is widely used in optoelectronics and optical thin film technology to prepare transparent conductive films, optical coatings, and window layers in photovoltaic devices. Its characteristics include good light transmittance, excellent electrical conductivity and chemical stability, and it is suitable for various high-tech applications.

[0003] Chinese patent application 201510964540.6 discloses a method for preparing a zinc oxide target and a method for preparing a zinc oxide film, wherein the zinc oxide target is prepared by providing a target raw material, subjecting the target raw material to a first ball milling treatment and then to a calcining treatment; subjecting the calcined powder to a second ball milling treatment and then to granulation to obtain pellets; subjecting the pellets to a cold isostatic pressing treatment to obtain a green blank; subjecting the green blank to a degreasing treatment in an air atmosphere to obtain a degreasing green blank, and then subjecting the green blank to anoxic sintering to obtain the zinc oxide target.

[0004] In this case, the zinc oxide target blank was first degreased and then subjected to oxygen-deficient sintering, which deoxidized the zinc oxide to a certain extent. The zinc oxide target changed from an intrinsic semiconductor to a semiconductor, thereby improving the conductivity of the zinc oxide target and meeting the requirements of the DC magnetron sputtering process for the conductivity of the target.

[0005] Chinese patent application 202210877198.6 discloses a ternary metal oxide ceramic target and a preparation method thereof, wherein zinc oxide, magnesium oxide and gallium oxide are mixed to obtain a mixed powder; the mixed powder is then molded, vacuum hot-pressed and sintered, and cooled in sequence to obtain a target blank; the target blank is then welded and post-processed in sequence to obtain the ternary metal oxide ceramic target.

[0006] In this case, the ternary ceramic target was obtained by adjusting the content and proportion of metal oxides in the ternary ceramic target, and then directly sintering after dry mixing, in which the doping amount of magnesium oxide was 13-15wt%.

[0007] In the above-mentioned related patents, there is no mention of how to improve the utilization rate of target raw materials.

[0008] The problem that this solution needs to solve: How to propose a method for preparing zinc oxide magnesium target with high raw material utilization rate. Summary of the invention

[0009] The purpose of this application is to propose a zinc oxide magnesium target material and a preparation method thereof, by pre-sintering zinc oxide powder and magnesium oxide powder, so that the surface of the target material tends to be flat after sintering, thereby improving material utilization.

[0010] To achieve the above object, the present application discloses a method for preparing a zinc-magnesium oxide target, comprising the following steps:

[0011] Step 1: Mix zinc oxide powder and magnesium oxide powder to obtain a mixed powder;

[0012] Step 2: The mixed powder is loaded into a mold for cold isostatic pressing, pre-sintering, and crushing to obtain pre-sintered powder;

[0013] Step 3: The pre-sintered powder is placed in a stainless steel sleeve, hot isostatically pressed, cooled to room temperature and pressure, and polished to obtain a zinc-magnesium oxide target;

[0014] The pre-sintering temperature is 800-900°C, and the pre-sintering time is 30-50 minutes.

[0015] Preferably, in step 1, the mass ratio of zinc oxide to magnesium oxide in the mixed powder is 90.5-90:0.5-10.

[0016] Preferably, in step 2, the cold isostatic pressing pressure is 50 to 90 MPa and the time is 5 to 10 min.

[0017] Preferably, the pre-sintering in step 2 needs to be performed under nitrogen protection.

[0018] Preferably, the particle size of the pre-sintered powder is ≤150μm; in practical applications, the crushed pre-sintered powder needs to be sieved through a sieve with a pore size of 150μm, and the pre-sintered powder remaining on the sieve after sieving needs to be crushed again until all the pre-sintered powder can pass through the sieve with a pore size of 150μm to ensure that the particle size of the pre-sintered powder is ≤150μm.

[0019] Preferably, the hot isostatic pressing sintering temperature is 1000-1100° C., the sintering pressure is 180-200 MPa, and the heat preservation and pressure holding time is 60-90 min.

[0020] In addition, a zinc oxide magnesium target material is also disclosed, which is prepared by the preparation method of the zinc oxide magnesium target material.

[0021] The beneficial effects of this application are:

[0022] The present application provides a method for preparing a zinc oxide magnesium target material. Through a pre-sintering process, raw material powder particles are diffused and combined to generate new crystalline particles and form a dense solid structure, so that the unit cell growth rate inside the target material can be made consistent during the sintering process, and the surface of the prepared zinc oxide magnesium target material is smoother, so that the material loss rate of the target material after grinding is reduced, and the material utilization rate is improved. DETAILED DESCRIPTION

[0023] In the description of this application, it should be noted that if the specific conditions are not specified in the examples, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0024] Example 1

[0025] Step 1: Mix zinc oxide and magnesium oxide powders in a mass ratio of 95:5 to obtain a mixed powder;

[0026] Step 2: The mixed powder is placed in a mold and cold pressed in a cold isostatic press at a pressure of 70 MPa for 7 minutes, and then pre-sintered at 850°C for 40 minutes in a nitrogen atmosphere, and crushed to obtain a pre-sintered powder with a particle size of ≤150 μm;

[0027] Step 3: The pre-sintered powder is placed in a stainless steel sleeve, and hot isostatic pressing is performed for 75 minutes at a temperature of 1050°C and a pressure of 190 MPa. After cooling to (normal temperature and pressure), the powder is polished to obtain a zinc-magnesium oxide target.

[0028] Example 2

[0029] The method is basically the same as Example 1, except that in step 1, the mass ratio of zinc oxide powder to magnesium oxide powder is 99.5:0.5.

[0030] Example 3

[0031] The method is basically the same as Example 1, except that in step 1, the mass ratio of zinc oxide powder to magnesium oxide powder is 90:10.

[0032] Example 4

[0033] It is basically the same as Example 1, except that the pre-sintering temperature is 800° C. and the time is 50 min.

[0034] Example 5

[0035] It is basically the same as Example 1, except that the pre-sintering temperature is 900° C. and the time is 30 minutes.

[0036] Example 6

[0037] It is basically the same as Example 1, except that the hot isostatic pressing sintering temperature is 1000° C., the pressure is 180 MPa, and the time is 90 min.

[0038] Example 7

[0039] It is basically the same as Example 1, except that the hot isostatic pressing sintering temperature is 1100° C., the pressure is 200 MPa, and the time is 60 min.

[0040] Example 8

[0041] The method is basically the same as Example 1, except that the hot isostatic pressing sintering temperature is 900°C.

[0042] Example 9

[0043] The method is basically the same as Example 1, except that the hot isostatic pressing sintering temperature is 1200°C.

[0044] Comparative Example 1

[0045] It is basically the same as Example 1, except that no pre-sintering process is performed in step 2.

[0046] Comparative Example 2

[0047] It is basically the same as Example 1, except that the pre-sintering temperature in step 2 is 700° C. and the time is 40 minutes.

[0048] Comparative Example 3

[0049] It is basically the same as Example 1, except that the pre-sintering temperature in step 2 is 1000° C. and the time is 40 minutes.

[0050] Performance Test:

[0051] Material utilization rate: When the zinc oxide magnesium target is taken out from the stainless steel sleeve, there will be uneven wrinkles on the surface of the target, so it is necessary to use a grinder to grind it to make the surface of the target flat and smooth before putting it into use.

[0052] Material utilization rate = weight of zinc oxide magnesium target after grinding / weight of zinc oxide powder and magnesium oxide powder * 100%

[0053] Relative density: Archimedean method

[0054] The target material performance test results are shown in Table 1:

[0055] Table 1

[0056] Group Material utilization Relative density Example 1 90.4％ 99.1％ Example 2 89.0％ 99.0％ Example 3 89.5％ 97.9％ Example 4 87.2％ 99.2％ Example 5 87.1％ 99.2％ Example 6 88.4％ 98.4％ Example 7 88.3％ 99.3％ Example 8 85.7％ 96.5％ Example 9 83.1％ 97.8％ Comparative Example 1 65.3％ 94.3％ Comparative Example 2 80.5％ 93.9％ Comparative Example 3 87.6％ 98.7％

[0057] Conclusion analysis:

[0058] 1. Through Example 1 and Comparative Example 1, combined with the data in Table 1, it can be seen that compared with Comparative Example 1, before the zinc oxide magnesium sintering step, a pre-sintering process is performed on the raw material powder, which can cause diffusion and combination between the raw material powder particles to generate new crystalline particles and form a dense solid structure. The material utilization rate of the target material can be increased by 25.1%, and the target material density can also be simultaneously increased by 4.8%.

[0059] 2. It can be seen from Examples 1-3 that in the zinc oxide magnesium target, the addition amount of magnesium oxide powder does not affect the material utilization rate of the target, but it will have a certain effect on the relative density of the target.

[0060] 3. Through Example 1, Examples 4-5 and Comparative Examples 2-3, in Example 1, the pre-sintering temperature is 850°C and the time is 40min;

[0061] In Example 4, the pre-sintering temperature is 800°C and the time is 50 min;

[0062] In Example 5, the pre-sintering temperature is 900°C and the time is 30 minutes;

[0063] In Comparative Example 2, the pre-sintering temperature is 700°C and the time is 40 min;

[0064] In Comparative Example 3, the pre-sintering temperature is 1000°C and the time is 40 min. Combined with the data in Table 1, it can be seen that when the pre-sintering temperature is between 800 and 900°C, the material utilization rate of the zinc oxide magnesium target will show a parabolic trend of first increasing and then decreasing, but the target utilization rate can be greater than 87%.

[0065] When the pre-sintering temperature is lower than 800°C, the energy provided during pre-sintering is insufficient to complete the diffusion between the powder particles and achieve better bonding, thereby reducing the material utilization rate. When the pre-sintering temperature is higher than 1000°C, the energy brought by pre-sintering is too high, causing excessive bonding between the powder particles. Some crystal cells have begun to grow, and subsequent crushing will cause the already grown crystal cells to be distorted. Although it has little effect on the target utilization rate and relative density, it will affect the application performance of the target.

[0066] 4. Through Example 1 and Examples 6-9, combined with the data in Table 1, it can be seen that when the temperature of hot isostatic pressing sintering is too low, the energy provided is insufficient to make the unit cells inside the target material grow together, so the growth rate of some unit cells that absorb less energy is slow, the target material shrinks too slowly, and the surface of the target material appears uneven;

[0067] When the hot isostatic pressing sintering temperature is too high, more energy is provided, and the unit cell growth rate inside the target material is too fast, but it will also cause abnormal growth of some unit cells, thereby affecting the shrinkage of the target material, resulting in an uneven target surface and reducing material utilization.

[0068] The above embodiments are preferred implementation modes of the present application, but the implementation modes of the present application are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods and shall be included in the protection scope of the present application.

Claims

1. A method for preparing a zinc-magnesium oxide target, characterized in that: The preparation method comprises the following steps: Step 1: Mix zinc oxide powder and magnesium oxide powder to obtain a mixed powder; Step 2: The mixed powder is loaded into a mold for cold isostatic pressing, pre-sintering, and crushing to obtain pre-sintered powder; Step 3: The pre-sintered powder is placed in a stainless steel sleeve, hot isostatically pressed, cooled to room temperature and pressure, and polished to obtain a zinc-magnesium oxide target; The pre-sintering temperature is 800-900° C., and the pre-sintering time is 30-50 minutes.

2. The method for preparing a zinc oxide magnesium target according to claim 1, characterized in that: In the step 1, the mass ratio of zinc oxide to magnesium oxide in the mixed powder is 99.5-90:0.5-10.

3. The method for preparing the zinc oxide magnesium target according to claim 1, characterized in that: In step 2, the cold isostatic pressing pressure is 50-90 MPa and the time is 5-10 min.

4. The method for preparing the zinc oxide magnesium target according to claim 1, characterized in that: The pre-sintering in step 2 needs to be performed under nitrogen protection.

5. The method for preparing the zinc oxide magnesium target according to claim 1, characterized in that: The particle size of the pre-sintered powder is ≤150 μm.

6. The method for preparing the zinc oxide magnesium target according to claim 1, characterized in that: The hot isostatic pressing sintering temperature is 1000-1100° C., the sintering pressure is 180-200 MPa, and the heat preservation and pressure holding time is 60-90 minutes.

7. A zinc-magnesium oxide target, characterized in that: The target is prepared by the method for preparing the zinc oxide magnesium target according to any one of claims 1 to 6.