MoTi target material and preparation method thereof
By preparing MoTi targets under a protective atmosphere, the problem of small production scale and high cost of molybdenum titanium targets in the prior art is solved, and high quality and low-cost MoTi targets are achieved, and the coating is improved. performance.
Patent Information
- Application Number
- CN202411403637.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-09
- Publication Date
- 2025-01-07
AI Technical Summary
In the prior art, the production scale of domestic high-quality molybdenum titanium targets is small, the output is low, and the cost is high, making it difficult to meet the requirements of large-scale industrial preparation, affecting the coating quality.
The ball mill mixing of molybdenum powder and titanium powder under a protective atmosphere, and the temperature and time of the heating and insulation stages are controlled through pre-pressing, sintering and hot pressing processes to produce MoTi targets with high density, high purity and small grain structure.
MoTi targets with high density, high purity, good conductivity and sputtering properties have been achieved, which reduces production costs, is suitable for large-scale production, and improves coating quality.
Smart Images
Figure CN119265527A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of semiconductor materials and relates to a target material preparation method, in particular to a MoTi target material and a preparation method thereof. Background Art
[0002] MoTi alloy target is a semiconductor material commonly used in the sputtering coating process. It is used to prepare thin films with excellent electrical, magnetic and optical properties. In the manufacturing process of large-scale semiconductor integrated circuits and solar cells, molybdenum-titanium alloy is usually used for PVD coating to form a barrier layer. Molybdenum-titanium alloy targets are usually sputtered by magnetron sputtering. The purity, density, grain assembly, conductivity and other performance parameters of the molybdenum-titanium target will affect the performance of the sputtered film, so the requirements for molybdenum-titanium targets are relatively high.
[0003] At present, the production scale of high-quality molybdenum-titanium targets in China is small, the output is low, and the cost is high. The molybdenum-titanium alloy produced by large-scale industrialization is usually difficult to meet the use requirements, which affects the subsequent coating quality. Summary of the invention
[0004] In view of the defects and shortcomings of the prior art, in a first aspect, the present invention provides a method for preparing a MoTi target; in a second aspect, the present invention provides a MoTi target.
[0005] Step 1, ball milling molybdenum powder and titanium powder under a protective atmosphere to obtain a mixed powder; Step 2, putting the mixed powder into a mold, pre-pressing it, and then releasing the pressure to obtain a rough blank; Step 3, sintering the rough blank in a vacuum atmosphere, the sintering stage includes a heating stage and a heating and heat preservation stage; In the heating stage, the temperature is raised to 850~1050℃ and kept warm for a certain period of time before entering the heating and keeping stage; In the heating and holding stage, the temperature is held for a certain time every time it rises by 80-120°C, until the temperature in the reaction system rises to 1350-1450°C and is held for a certain time to obtain an intermediate product; Step 4, hot pressing the intermediate product at 1350-1450° C., and keeping the temperature and pressure for a certain period of time, and then cooling and demolding with the furnace to obtain the MoTi target material.
[0006] Preferably, in the mixed powder, titanium powder accounts for 20-40wt%, and the remainder is molybdenum powder and inevitable impurities.
[0007] Preferably, the purity of the molybdenum powder is greater than 99.95%, and the D50 of the molybdenum powder is 5-8 μm; the purity of the titanium powder is greater than 99.95%, and the D50 of the titanium powder is 30-45 μm.
[0008] Preferably, in step 1, the ball-to-material ratio (wt%) during ball milling is 1:1.5-2.5; the ball milling speed is 300-400 r / min; and the ball milling time is 10-18 h.
[0009] Preferably, the protective gas providing the protective atmosphere is any one or both of argon and nitrogen.
[0010] Preferably, in step 2, the pressure increase rate during pre-pressing is 0.1-0.3 MPa / min; the pre-pressing pressure is 6-10 MPa; and the pressure holding time is 10-15 min.
[0011] Preferably, in step 3, the pressure of the vacuum atmosphere is less than 5 Pa.
[0012] Preferably, in step 3, the heating stage includes a first stage and a second stage. In the first stage, the heating rate is 8-10°C / min and the temperature is increased to 600-800°C, and then the second stage is entered; in the second stage, the heating rate is reduced to 5-8°C / min, the temperature is increased to 850-1050°C, and the temperature is kept for 30-60min.
[0013] Preferably, in step 3, during the heating and insulation stage, the initial heating rate is 5-6°C / min, and the heating rate decreases by 1-2°C / min every time the temperature rises by 80-120°C.
[0014] Preferably, in step 3, during the heating and heat preservation stage, the temperature is kept warm for 30 to 60 minutes every time the temperature is increased by 80 to 120°C.
[0015] Preferably, in step 4, the hot pressing process adopts a staged pressurization method, first pressurizing to 20-25 MPa at a rate of 0.25-0.35 MPa / min; and then pressurizing to 35-40 MPa at a rate of 0.1-0.2 MPa / min.
[0016] Preferably, in step 4, the heat preservation and pressure preservation time is 90 to 150 minutes.
[0017] In a second aspect, the present invention provides a MoTi target material prepared by the above preparation method.
[0018] Compared with the prior art, the present invention has the following obvious beneficial effects: The present invention provides a method for preparing a MoTi target material, and the prepared target material has the excellent characteristics of high density, high purity, fine grain structure, good electrical conductivity, good sputtering performance, and not easy to crack. In addition, the preparation method provided by the present invention has low equipment requirements, can reduce errors in the production process, can carry out large-scale production under the premise of ensuring the quality of the target material, reduce production costs, and is conducive to the promotion and marketization of MoTi target materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is the SEM image of the target material prepared in Example 1. DETAILED DESCRIPTION
[0020] The present invention provides the following specific technical solutions.
[0021] In a first aspect, the present invention provides a method for preparing a MoTi target, comprising the following steps: Step 1, ball milling molybdenum powder and titanium powder under a protective atmosphere to obtain a mixed powder; Step 2, putting the mixed powder into a mold, pre-pressing it, and then releasing the pressure to obtain a rough blank; Step 3, sintering the rough blank in a vacuum atmosphere, the sintering stage includes a heating stage and a heating and heat preservation stage; In the heating stage, the temperature is raised to 850~1050℃ and kept warm for a certain period of time before entering the heating and keeping stage; In the heating and holding stage, the temperature is held for a certain time every time it rises by 80-120°C, until the temperature in the reaction system rises to 1350-1450°C and is held for a certain time to obtain an intermediate product; Step 4, hot pressing the intermediate product at 1350-1450° C., and keeping the temperature and pressure for a certain period of time, and then cooling and demolding with the furnace to obtain the MoTi target material.
[0022] In large-scale production processes, the production equipment is large in size, and there are errors in the temperature and pressure of different areas in the equipment. The preparation method provided by the present invention has low equipment requirements, can reduce the errors in the production process, and can be produced on a large scale under the premise of ensuring the quality of the target material, which is conducive to the promotion and marketization of MoTi target materials. In addition, the MoTi target material prepared by the preparation method provided by the present invention has the excellent characteristics of high density, high purity, fine grain structure, good conductivity, good sputtering performance, and not easy to crack.
[0023] Preferably, in the mixed powder, titanium powder accounts for 20-40wt%, and the remainder is molybdenum powder and inevitable impurities.
[0024] Preferably, the purity of the molybdenum powder is greater than 99.95%, and the D50 of the molybdenum powder is 5-8 μm; the purity of the titanium powder is greater than 99.95%, and the D50 of the titanium powder is 30-45 μm.
[0025] Preferably, in step 1, the ball-to-material ratio (wt%) during ball milling is 1:1.5-2.5; the ball milling speed is 300-400 r / min; and the ball milling time is 10-18 h.
[0026] Preferably, in step 2, the pressure increase rate during pre-pressing is 0.1-0.3 MPa / min; the pre-pressing pressure is 6-10 MPa; and the pressure holding time is 10-15 min.
[0027] Preferably, in step 3, the pressure of the vacuum atmosphere is less than 5 Pa.
[0028] Preferably, in step 3, the heating stage includes a first stage and a second stage. In the first stage, the heating rate is 8-10°C / min and the temperature is increased to 600-800°C, and then the second stage is entered; in the second stage, the heating rate is reduced to 5-8°C / min, the temperature is increased to 850-1050°C, and the temperature is kept for 30-60min.
[0029] The heating rate is fast at low temperature and slow at high temperature, which is conducive to a uniform temperature field, making the texture of the target material uniform and the grains fine, thus improving the quality of the target material.
[0030] Preferably, in step 3, during the heating and insulation stage, the initial heating rate is 5-6°C / min, and the heating rate decreases by 1-2°C / min every time the temperature rises by 80-120°C.
[0031] Preferably, in step 3, during the heating and heat preservation stage, the temperature is kept warm for 30 to 60 minutes every time the temperature is increased by 80 to 120°C.
[0032] During the heating and insulation stage, each time the temperature is raised to a certain level, it is maintained for a certain period of time, which is beneficial to uniform temperature field, improving the uniformity of the target material, and further improving the quality of the target material.
[0033] Preferably, in step 4, the hot pressing process adopts a staged pressurization method, first pressurizing to 20-25 MPa at a rate of 0.25-0.35 MPa / min; and then pressurizing to 35-40 MPa at a rate of 0.1-0.2 MPa / min.
[0034] By applying pressure in stages, on the one hand, it matches the hot pressing equipment; on the other hand, it allows the sintering neck to fully grow and combine in the early stage of sintering, with a fast densification rate. In the later stage of sintering, densification is mainly achieved through creep, which requires a slow pressure increase rate. The staged pressurization can improve the density of the target material while also obtaining a uniform and fine grain structure.
[0035] Preferably, in step 4, the heat preservation and pressure preservation time is 90 to 150 minutes.
[0036] In a second aspect, the present invention provides a MoTi target material prepared by the above preparation method.
[0037] In order to make the technical problems, technical solutions and technical advantages to be solved by the present invention more clear, they will be described in detail below with reference to specific examples, but the protection scope of the present invention is not limited to the following specific embodiments.
[0038] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.
[0039] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.
[0040] Embodiment 1: A method for preparing a MoTi target comprises the following steps: Step 1, mix molybdenum powder and titanium powder, the molybdenum powder is 30wt%, and the titanium powder is 70wt%, and the mixed powder of molybdenum powder and titanium powder is transferred to a ball mill for ball milling. During ball milling, the mixed powder of molybdenum powder and titanium powder is placed in an argon atmosphere, the ball milling medium is zirconia balls, the ball-to-material ratio is 1:2, the ball milling speed is 350r / min, and the ball milling time is 14h to obtain a mixed powder.
[0041] Step 2: Place the mixed powder into a mold for pre-compression at a pre-compression pressure of 6 MPa. Maintain the pressure for 10 minutes and then release it to obtain a rough blank.
[0042] Step 3, transfer the rough blank and the mold to the hot pressing furnace, maintain the vacuum pressure in the hot pressing furnace below 5 Pa, enter the heating stage, and heat up to 600°C at a heating rate of 10°C / min; adjust the heating rate to 7°C / min to heat up to 950°C, keep warm for 30 minutes, then enter the heating and insulation stage, adjust the heating rate to 6°C / min to heat up to 1050°C, and keep warm for 30 minutes; adjust the heating rate to 5°C / min to heat up to 1150°C, and keep warm for 30 minutes; adjust the heating rate to 4°C / min to heat up to 1250°C, and after the heating is completed, keep warm for 30 minutes; adjust the heating rate to 3°C / min to heat up to 1350°C, and keep warm for 30 minutes to obtain an intermediate product.
[0043] Step 4, after the insulation is completed, the intermediate product is pressurized at a temperature of 1350°C, firstly pressurized to 25MPa at a pressurization rate of 0.35MPa / min; then pressurized to 35MPa at a pressurization rate of 0.15MPa / min, and the temperature and pressure are maintained for 120min.
[0044] Step 5, after the heat preservation and pressure preservation are completed, the target is cooled with the furnace and demolded to obtain the MoTi target.
[0045] Embodiment 2: A method for preparing a MoTi target comprises the following steps: Step 1, mixing molybdenum powder and titanium powder, the molybdenum powder is 20wt%, and the titanium powder is 80wt%, and the mixed powder of the molybdenum powder and the titanium powder is transferred to a ball mill for ball milling. During the ball milling, the mixed powder of the molybdenum powder and the titanium powder is placed in an argon atmosphere, the ball milling medium is zirconia balls, the ball-to-material ratio is 1:1.5, the ball milling speed is 300r / min, and the ball milling time is 10h to obtain a mixed powder.
[0046] Step 2: Place the mixed powder into a mold for pre-compression at a pre-compression pressure of 8 MPa. Maintain the pressure for 12 minutes and then release it to obtain a rough blank.
[0047] Step 3, transfer the rough blank and the mold to the hot pressing furnace, maintain the vacuum pressure in the hot pressing furnace below 5Pa, enter the heating stage, and heat up to 700°C at a heating rate of 8°C / min; then adjust the heating rate to 8°C / min to heat up to 850°C, keep warm for 30 minutes, then enter the heating and insulation stage, adjust the heating rate to 6°C / min to heat up to 970°C, keep warm for 30 minutes; adjust the heating rate to 5°C / min to heat up to 1090°C, keep warm for 30 minutes; adjust the heating rate to 4°C / min to heat up to 1210°C, keep warm for 30 minutes; adjust the heating rate to 3°C / min to heat up to 1350°C, keep warm for 30 minutes, and obtain the intermediate product.
[0048] Step 4, after the insulation is completed, the intermediate product is pressurized at a temperature of 1350°C, firstly pressurized to 20MPa at a pressurization rate of 0.25MPa / min; then pressurized to 35MPa at a pressurization rate of 0.1MPa / min, and the temperature and pressure are maintained for 120min.
[0049] Step 5, after the heat preservation and pressure preservation are completed, the target is cooled with the furnace and demolded to obtain the MoTi target.
[0050] Embodiment 3: A method for preparing a MoTi target comprises the following steps: Step 1, mixing molybdenum powder and titanium powder, the molybdenum powder is 40wt%, and the titanium powder is 60wt%, and the mixed powder of the molybdenum powder and the titanium powder is transferred to a ball mill for ball milling. During the ball milling, the mixed powder of the molybdenum powder and the titanium powder is placed in an argon atmosphere, the ball milling medium is zirconia balls, the ball-to-material ratio is 1:2.5, the ball milling speed is 400r / min, and the ball milling time is 18h to obtain a mixed powder.
[0051] Step 2: Place the mixed powder into a mold for pre-compression at a pre-compression pressure of 10 MPa. Maintain the pressure for 15 minutes and then release it to obtain a rough blank.
[0052] Step 3, transfer the rough blank and the mold to the hot pressing furnace, maintain the vacuum pressure in the hot pressing furnace below 5 Pa, enter the heating stage, and heat up to 800°C at a heating rate of 9°C / min; adjust the heating rate to 5°C / min to heat up to 1050°C, keep warm for 30 minutes, then enter the heating and insulation stage, adjust the heating rate to 6°C / min to heat up to 1170°C, keep warm for 30 minutes; adjust the heating rate to 4°C / min to heat up to 1210°C, keep warm for 30 minutes; adjust the heating rate to 3°C / min to heat up to 1290°C, keep warm for 30 minutes; adjust the heating rate to 2°C / min to heat up to 1410°C to obtain an intermediate product.
[0053] Step 4, after the insulation is completed, the intermediate product is pressurized at a temperature of 1410°C, firstly pressurized to 25MPa at a pressurization rate of 0.3MPa / min; then pressurized to 38MPa at a pressurization rate of 0.2MPa / min, and the temperature and pressure are maintained for 120min.
[0054] Step 5, after the heat preservation and pressure preservation are completed, the target is cooled with the furnace and demolded to obtain the MoTi target.
[0055] Embodiment 4: A method for preparing a MoTi target comprises the following steps: Step 1, mix molybdenum powder and titanium powder, the molybdenum powder is 35wt%, and the titanium powder is 65wt%, and the mixed powder of molybdenum powder and titanium powder is transferred to a ball mill for ball milling. During ball milling, the mixed powder of molybdenum powder and titanium powder is placed in an argon atmosphere, the ball milling medium is zirconia balls, the ball-to-material ratio is 1:2, the ball milling speed is 380r / min, and the ball milling time is 16h to obtain a mixed powder.
[0056] Step 2: Place the mixed powder into a mold for pre-compression at a pre-compression pressure of 7 MPa. Maintain the pressure for 12 minutes and then release it to obtain a rough blank.
[0057] Step 3, transfer the rough blank and the mold to the hot pressing furnace, maintain the vacuum pressure in the hot pressing furnace below 5 Pa, enter the heating stage, and heat up to 800°C at a heating rate of 10°C / min; adjust the heating rate to 8°C / min to heat up to 1000°C, keep warm for 30 minutes, then enter the heating and insulation stage, adjust the heating rate to 6°C / min to heat up to 1080°C, keep warm for 30 minutes; adjust the heating rate to 5°C / min to heat up to 1160°C, keep warm for 30 minutes; adjust the heating rate to 4°C / min to heat up to 1240°C, keep warm for 30 minutes; adjust the heating rate to 3°C / min, heat up to 1320°C, keep warm for 30 minutes; adjust the heating rate to 2°C / min to heat up to 1400°C / min, keep warm for 30 minutes, and obtain the intermediate product.
[0058] Step 4, after the insulation is completed, the intermediate product is pressurized at a temperature of 1400°C / min, firstly pressurized to 25MPa at a pressurization rate of 0.3MPa / min; then pressurized to 38MPa at a pressurization rate of 0.2MPa / min, and the temperature and pressure are maintained for 120min.
[0059] Step 5, after the heat preservation and pressure preservation are completed, the target is cooled with the furnace and demolded to obtain the MoTi target.
[0060] Embodiment 5: The difference from Example 1 is that in step 3, after entering the heating and insulation stage, the heating rate is always 6°C / min.
[0061] Comparative Example 1: The difference from Example 1 is that in step 3, the heating rate is 8°C / min and the temperature is raised to 1380°C and kept at this temperature for 30 minutes.
[0062] Comparative Example 2: The difference from Example 1 is that in step 3, in the heating stage, the heating rate is 10°C / min to raise the temperature to 950°C, and after keeping warm for 30 minutes, it enters the heating and keeping stage; the heating rate is adjusted to 6°C / min to raise the temperature to 1350°C, and keep warm for 30 minutes.
[0063] Comparative Example 3: The difference from Example 1 is that the target temperature of the heating and heat preservation stage in step 3 is 1330°C; the heat preservation and pressure holding temperature in step 4 is also 1330°C.
[0064] Comparative Example 4: The difference from Example 1 is that the target temperature of the heating and heat preservation stage in step 3 is 1500°C; the heat preservation and pressure holding temperature in step 4 is also 1500°C.
[0065] The target materials prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were subjected to relative density tests and electrical conductivity tests, wherein the relative density was directly tested using the traditional Archimedean method.
[0066] As can be seen from Table 1, the density of the target materials prepared in Examples 1 to 3 of the present invention is all above 99%, and the purity is greater than 99.95%, which proves that the preparation method provided by the present invention can prepare a target material with superior performance.
[0067] By comparing the target materials obtained in Example 1 and Comparative Example 1, it can be proved that the multi-stage heating and insulation process provided by the present invention is beneficial to improving the density and morphology of the target material, and improving the yield and quality of the target material; the grains of the obtained target material are finer, which is beneficial to subsequent coating.
[0068] Comparing the target materials obtained in Example 1 and Comparative Example 2, it can be further proved that the multi-stage heating and heat preservation process provided by the present invention is conducive to improving the density and morphology of the target material, and the grains of the obtained target material are finer.
[0069] Comparing the targets prepared in Example 1 with those prepared in Comparative Examples 3 and 4, it can be proved that the final target material calcining temperature proposed in the present invention is beneficial to improving the density and morphology of the target material.
[0070] Figure 1 This is a SEM image of the target material prepared in Example 1 of the present invention. Figure 1 The gray part is Mo grains, and the white part is Ti grains. Figure 1 It can be seen that the Mo phase and the Ti phase in the MoTi target are uniformly and densely distributed in microscopic form, the grains are fine, and there is no hole defect, which proves that the process for preparing the MoTi target of the present invention can obtain a MoTi target with excellent performance.
[0071] The embodiments described above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope of the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A method for preparing a MoTi target, characterized in that: The steps include: Step 1, ball milling molybdenum powder and titanium powder under a protective atmosphere to obtain a mixed powder; Step 2, putting the mixed powder into a mold, pre-pressing it, and then releasing the pressure to obtain a rough blank; Step 3, sintering the rough blank in a vacuum atmosphere, the sintering stage includes a heating stage and a heating and insulation stage; In the heating stage, the temperature is raised to 850~1050℃ and kept warm for a certain period of time before entering the heating and keeping stage; In the heating and holding stage, the temperature is held for a certain time every time it rises by 80-120°C, until the temperature in the reaction system rises to 1350-1450°C and is held for a certain time to obtain an intermediate product; Step 4, hot pressing the intermediate product at 1350-1450° C., and keeping the temperature and pressure for a certain period of time, and then cooling and demolding with the furnace to obtain the MoTi target material.
2. The method for preparing a MoTi target according to claim 1, characterized in that: In the mixed powder, titanium powder accounts for 20-40wt%, and the remainder is molybdenum powder and inevitable impurities.
3. The method for preparing a MoTi target according to claim 1 or 2, characterized in that: In step 3, the heating stage includes a first stage and a second stage. In the first stage, the heating rate is 8-10°C / min and the temperature is increased to 600-800°C, and then the second stage is entered; in the second stage, the heating rate is reduced to 5-8°C / min, the temperature is increased to 850-1050°C, and the temperature is kept for 30-60 minutes.
4. The method for preparing a MoTi target according to claim 1, characterized in that: In step 3, during the heating and insulation stage, the initial heating rate is 5-6°C / min, and the heating rate decreases by 1-2°C / min every time the temperature rises by 80-120°C.
5. The method for preparing a MoTi target according to claim 1 or 4, characterized in that: In step 3, during the heating and heat preservation stage, the temperature is kept for 30 to 60 minutes every time the temperature rises by 80 to 120°C.
6. The method for preparing a MoTi target according to claim 1, characterized in that: In step 4, the hot pressing process adopts a staged pressurization method, first pressurizing to 20~25MPa at a rate of 0.25~0.35MPa / min; then pressurizing to 35~40MPa at a rate of 0.1~0.2MPa / min.
7. The method for preparing a MoTi target according to claim 1 or 6, characterized in that: In step 2, the pressure increase rate during pre-pressing is 0.1~0.3MPa / min; the pre-pressing pressure is 6~10MPa; and the pressure holding time is 10~15min.
8. The method for preparing a MoTi target according to claim 1, characterized in that: In step 4, the heat preservation and pressure preservation time is 90 to 150 minutes.
9. The method for preparing a MoTi target according to claim 1, characterized in that: The purity of molybdenum powder is greater than 99.95%, and the D50 of molybdenum powder is 5~8μm; the purity of titanium powder is greater than 99.95%, and the D50 of titanium powder is 30~45μm.
10. A MoTi target material, characterized in that: Prepared by the preparation method according to any one of claims 1 to 9.