Low-cost target forming and binding method

Abstract

The invention provides a low-cost target material forming and binding method, which comprises the following steps of: firstly carrying out mould pressing or cold isostatic pressing on powder to obtain blanks, then prefabricating a binding layer on a binding surface of a back plate, prefabricating an isolating layer on the outer surface of a core mould, the inner surface of a sheath and a contact surface between the blanks, combining and welding the blanks, the back plate, the core mould and the sheath, degassing, and carrying out hot isostatic pressing, so as to obtain the low-cost target material. And finally machining to obtain the finished target material. The structure and process design of the invention have the following characteristics: (1) target material forming and binding can be realized at the same time through hot isostatic pressing, and an additional binding process of the target material is avoided; (2) the target blank subjected to hot isostatic pressing tends to be subjected to near-net forming, and the finished target can be obtained only through a small amount of finish machining; and (3) the core mold, the back plate and the sheath can be repeatedly used for multiple times. The production cost can be effectively reduced, and batch production is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of manufacturing of magnetron sputtering target material, and relates to a target material forming and binding method, in particular to a low-cost target material forming and binding method. BACKGROUND

[0002] Magnetron sputtering belongs to a kind of physical vapor deposition (PVD) thin film preparation technology, and is a common technology for preparing thin films, which has been widely used in the field of film coating. The magnetron sputtering target material is usually composed of a target material layer and a backing plate layer. The target material layer is the film coating raw material, and the backing plate layer is the target material support and heat dissipation component. In the existing target material preparation technology, the target material forming and backing plate binding processes are usually carried out separately, that is, after the target material is formed through powder metallurgy, melting and casting, plastic deformation and other processes, it is machined into the required target material shape, and then the target material layer and the backing plate layer are bound and combined through binding. The process flow is long.

[0003] Hot isostatic pressing belongs to a kind of advanced sintering forming technology, and its principle is to promote powder sintering forming under the action of high temperature and high pressure. With the development of diversified target materials, hot isostatic pressing technology plays an increasingly important role in the field of target material forming. In the hot isostatic pressing technology, the canning process is a traditional process, that is, the parts to be formed or the powder are put into the can, the can is closed by welding, and the can is removed by machining or chemical method after hot isostatic pressing. Therefore, the can is often used as a consumable product, which accounts for a large cost in powder metallurgy forming. At present, there is no related report about the reuse of the can.

[0004] The existing target material forming and binding process flow based on hot isostatic pressing is long, and some steps can be further reduced in cost by optimizing the structure design or improving the efficiency of auxiliary materials. SUMMARY

[0005] In order to reduce the production cost of target material and enrich the target material preparation technology, the present application provides a target material forming and binding method. The method has a short process flow, low production cost, can realize batch production, and is suitable for the production and manufacturing of various types of target materials.

[0006] The above features of the present application are mainly realized by the following process technology: a low-cost target material forming and binding method, comprising:

[0007] The target material raw powder is pressed into a compact;

[0008] A core mold is prepared, and a fixed groove matching the size of the backing plate is prepared on the outer surface of the core mold; an insulation layer is prepared on the outer surface of the core mold, the inner surface of the can, and the contact surface between the compact;

[0009] The backing plate is installed in the fixed groove of the core mold, the compact is placed on the outer surface of the core mold and the backing plate, and the outermost layer is installed with the can and welded;

[0010] The cladding after welding is subjected to thermal degassing;

[0011] The cladding after thermal degassing is subjected to hot isostatic pressing;

[0012] The cladding after hot isostatic pressing is processed to remove the weld, and the cladding is removed;

[0013] The target material blank is obtained by removing other materials from the mandrel, the insulation layer on the target material blank is removed, and the finished target material is obtained after finishing the target material blank.

[0014] Preferably, the removed cladding and the used target material waste are evaluated to determine whether they can be reused, and if the evaluation is passed, the cladding is flattened, the residual target is removed, and the cladding or the back plate is reused.

[0015] Preferably, the cladding recycling is evaluated according to the effective thickness of the cladding waste, the effective thickness of the aluminum alloy cladding waste is ≥0.8mm, the effective thickness of the steel cladding waste is ≥1.2mm, and the effective thickness of the titanium alloy cladding waste is ≥2mm, and the back plate recycling is judged according to the size of the used target material waste, i.e. the back plate, and if the size of the back plate is within the size tolerance, the back plate can be reused.

[0016] Preferably, the original powder is one of elemental metal powder, single alloy powder, single compound powder, or a mixture of two or more powders, and if two or more powders are mixed, the absolute difference of the laser particle size D50 of different powders is ≤20μm.

[0017] Preferably, the preparation method of the compact is powder molding or cold isostatic pressing, and the relative density of the compact is ≥60%.

[0018] Preferably, if a binding layer is needed, the binding layer is prepared on the binding surface of the back plate before the back plate is installed in the fixing groove of the mandrel; the binding layer is a combined layer of the target material and the back plate, and the material is a composite layer composed of one or more of copper, nickel, and silver, and the preparation method of the binding layer is electroplating or spraying.

[0019] Preferably, the mandrel is a material that does not deform during hot isostatic pressing, and the material is selected to match the hot isostatic pressing temperature; when the hot isostatic pressing temperature is 300℃-600℃, the mandrel material is selected to be heat-resistant steel, molybdenum alloy, or tungsten alloy; when the hot isostatic pressing temperature is 600℃-1300℃, the mandrel material is selected to be molybdenum alloy or tungsten alloy; and when the hot isostatic pressing temperature is 1300℃-1600℃, the mandrel material is tungsten alloy.

[0020] Preferably, the sheath material is matched with the temperature of the hot isostatic pressing, and is made by shearing, bending and forming the plate material; the temperature of the hot isostatic pressing is 300-600 DEG C, the sheath material is aluminum alloy, the temperature of the hot isostatic pressing is 600-1300 DEG C, the sheath material is steel, the temperature of the hot isostatic pressing is 1300-1600 DEG C, and the sheath material is titanium alloy.

[0021] Preferably, the thermal degassing process is at a temperature of 200-1000 DEG C, for 2-10 hours, and the vacuum degree is less than or equal to 1*10 -3 Pa.

[0022] Preferably, the hot isostatic pressing process is at a temperature of 300-1600 DEG C, for 1-6 hours, and the pressure is 80-200 MPa; after the hot isostatic pressing, the relative density of the target material is greater than or equal to 99%, and the binding strength between the target material and the back plate is greater than or equal to 99%.

[0023] Compared with the prior art, the present application has at least the following beneficial effects:

[0024] In the embodiment of the present application, the target material is densified and formed by hot isostatic pressing, and the target material is bound with the back plate at the same time, so that the manufacturing process of the target material is reduced. Through special sheath structure design, the core mold does not deform during the hot isostatic pressing process, and the core mold can be reused. The target material and the back plate that are well bound are close to near-net-shape, and only a small amount of processing is needed to obtain the target material product. Through the design of the insulation layer, the outer sheath can be removed after the hot isostatic pressing and processing, and the outer sheath can be reused. After the use of the target material is completed, the back plate can be recycled. Through the optimization of the process flow and the structure design, the present application realizes the low-cost production of the magnetron sputtering target material, can realize batch production, and has a good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The figure is a target material forming and binding flowchart of the present application;

[0026] Figure 2 The figure is a core mold schematic diagram of the present application;

[0027] Figure 3 The figure is a hot isostatic pressing sheath assembly schematic diagram of the present application;

[0028] Figure 4 The figure is a target material and back plate binding interface diagram of the present application. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the present application, the following will combine the drawings of the present application with specific embodiments to further describe the present application in detail: Figures 1-4 The present application will be further described in detail in combination with specific embodiments:

[0030] A low-cost target material forming and binding method, as shown in the figure, mainly includes the following steps: Figure 1

[0031] ​(1) Press the original powder into a green compact 5;

[0032] (2) Preform the binding layer 4 on the binding surface of the backing plate;

[0033] (3) Preform the insulation layer 2 on the outer surface of the core mold (as shown in Figure 2 ), the inner surface of the sheath, and the contact surface between the green compact.

[0034] (4) As shown in Figure 3 , assemble the core mold 1, the backing plate 3, the green compact 5, and the sheath 6 into a hot isostatic pressing sheath and weld them.

[0035] (5) Perform thermal degassing on the welded sheath.

[0036] (6) Perform hot isostatic pressing on the sheath after thermal degassing.

[0037] (7) Process the sheath after hot isostatic pressing to remove the welds, remove the sheath waste, and recycle it for future use.

[0038] (8) Take out the target material blank from the groove of the core mold 1, reserve the core mold 1 for repeated use, and process the target material blank to obtain a finished target material. Recycle the used target material for future use.

[0039] (9) Evaluate whether the sheath waste and the target material waste can be reused. If the evaluation is passed, flatten the sheath, remove the residual target, and reuse the sheath or the backing plate, and repeat steps (1) to (9). If the evaluation is not passed, manufacture a new sheath or a new backing plate, and repeat steps (1) to (9).

[0040] As a preferred solution, the original powder in step (1) can be a single metal powder, a single alloy powder, a single compound powder, or a mixed powder composed of two or more powders. If two or more powders are mixed, the absolute difference between the laser particle sizes D50 of different powders is ≤20 μm.

[0041] As a preferred solution, the green compact preparation method in step (1) is powder molding or cold isostatic pressing, and the relative density of the green compact is ≥60%.

[0042] As a preferred solution, the binding layer in step (2) is a bonding layer between the target material and the backing plate. If necessary, the material can be copper, nickel, silver, or a composite layer composed of two or more of the foregoing, and the binding layer can be prepared by electroplating or spraying.

[0043] As a preferred solution, the insulation layer in step (3) is a barrier layer to prevent diffusion and bonding during hot isostatic pressing of the contact surface. The material can be graphite paper, boron nitride coating, or aluminum oxide coating.

[0044] As a preferred solution, the core mold in step (4) is a non-deformation material such as heat-resistant steel, molybdenum alloy or tungsten alloy, and a fixed groove matching the size of the back plate is pre-fabricated on the outer surface. The number and size of the fixed groove are determined according to the final product target material. The material is selected to match the hot isostatic pressing temperature, which is 300-600°C. The core mold material can be heat-resistant steel, molybdenum alloy or tungsten alloy, the hot isostatic pressing temperature is 600-1300°C, the core mold material can be molybdenum alloy or tungsten alloy, the isostatic pressing temperature is 1300-1600°C, and the core mold material is tungsten alloy.

[0045] As a preferred solution, the sleeve in step (4) is made of sheet material such as aluminum alloy, steel (carbon steel, stainless steel) or titanium alloy, which is cut and bent. The material is selected to match the hot isostatic pressing temperature, which is 300-600°C. The sleeve material is aluminum alloy, the hot isostatic pressing temperature is 600-1300°C, the sleeve material is steel (carbon steel, stainless steel), and the isostatic pressing temperature is 1300-1600°C. The sleeve material is titanium alloy.

[0046] As a preferred solution, the heat degassing process in step (5) has a temperature of 200-1000°C, a time of 2-10h, and a vacuum degree of ≤1×10 -3 Pa.

[0047] As a preferred solution, the hot isostatic pressing process in step (6) has a temperature of 300-1600°C, a time of 1-6h, and a pressure of 80-200MPa. After hot isostatic pressing, the target material has a relative density of ≥99% and the target material and back plate binding surface have a binding law of ≥99%.

[0048] As a preferred solution, the sleeve recycling evaluation method in step (9) judges the effective thickness of the sleeve waste. Aluminum alloy sleeve waste with an effective thickness of ≥0.8mm can be reused, steel sleeve waste with an effective thickness of ≥1.2mm can be reused, and titanium alloy sleeve waste with an effective thickness of ≥2mm can be reused.

[0049] As a preferred solution, the back plate recycling evaluation method in step (9) judges the size of the back plate. If the back plate is within the size tolerance range, it can be reused.

[0050] Example 1

[0051] This embodiment provides a forming and binding method for a magnetron sputtering target material with a target material specification of 92*642*5mm, a target material material of Ti / Al 33 / 67at%, a back plate specification of 100*650*5mm, and a back plate material of oxygen-free copper. The target material and the back plate are bound to each other.

[0052] Ti powder with laser particle size D50 = 29 μm and Al powder with laser particle size D50 = 26 μm are mixed uniformly in the component ratio Ti / Al 33 / 67 at% by a three-dimensional mixer, and then loaded into a powder forming hydraulic press to press a compact, the compact specification is 120*670*10mm, and the compact relative density is 63%. The core mold material is 253MA heat-resistant steel, the outer size is 240*240*1340mm, the core mold groove size is 100.5*650.5*5mm, the oxygen-free copper back plate binding surface is pickled and dried, the core mold outer surface, the inner surface of the cladding, and the contact surface between the compact are pasted with 0.2mm thick graphite paper, there is no exposed part on the surface of the pasted graphite paper, then the back plate binding surface is loaded into the core mold outwardly, the compact is attached to the binding surface of the back plate, and finally a 4mm thick 1010 aluminum alloy cladding is attached and welded. The degassing process is at a temperature of 300℃ for 3h, a vacuum degree ≤1×10 -3 Pa. The hot isostatic pressing process is at a temperature of 430℃ for 2h, a pressure of 135MPa, and finally the target material is machined, the target material relative density is 99.56%, the target material and the back plate binding surface binding law is 99.17%, and the microstructure of the binding surface is shown in the figure. In this embodiment, the back plate is almost not deformed, the back plate can be reused for ≥15 times, the cladding is thinned by about 0.4mm after single oxidation, the cladding can be reused for ≥8 times, and the production cost can be effectively reduced. Figure 4 The microstructure of the binding surface is shown in the figure. In this embodiment, the back plate is almost not deformed, the back plate can be reused for ≥15 times, the cladding is thinned by about 0.4mm after single oxidation, the cladding can be reused for ≥8 times, and the production cost can be effectively reduced.

[0053] Example 2

[0054] This embodiment provides a forming and binding method of a magnetron sputtering target material, the target material specification is 130*750*5mm, the target material material is Ti / Si85 / 15at%, the back plate specification is 138*760*5mm, the back plate material is TA2, and the target material and the back plate are bound to each other.

[0055] Ti powder with laser particle size D50 = 44 μm and Ti5Si3 powder with laser particle size D50 = 39 μm are mixed uniformly in the component ratio Ti / Si85 / 15at% by a three-dimensional mixer, and then loaded into a rubber sleeve and cold isostatic pressed into a compact, the machined compact specification is 150*780*10mm, and the compact relative density is 68%. The core mold material is MoLa alloy, the outer size is 300*300*780mm, the core mold groove size is 138.5*760.5*5mm, the TA2 back plate binding surface is pickled and dried, the core mold outer surface, the inner surface of the cladding, and the contact surface between the compact are sprayed with boron nitride with a thickness ≤0.3mm, there is no exposed part on the surface of the sprayed boron nitride, then the back plate binding surface is loaded into the core mold outwardly, the compact is attached to the binding surface of the back plate, and finally a 4mm thick 20# cladding is attached and welded. The degassing process is at a temperature of 450℃ for 5h, a vacuum degree ≤1×10 -3Pa. Hot isostatic pressing process is temperature 950℃, time 3h, pressure 135MPa, finally machining to get target material, target material relative density 99.21%, target material and back plate binding surface binding law 99.55%. In this embodiment, the back plate is almost no deformation, the back plate can be reused ≥15 times, the package sleeve is thinned by oxidation about 0.8mm single time, the package sleeve can be reused ≥2 times, which can effectively reduce the production cost.

[0056] Example 3

[0057] This embodiment provides a target material specification is 102*540*5mm, target material material is W / Ti90 / 10wt%, back plate specification is 110*550*5mm, back plate material is oxygen-free copper, the forming and binding method of magnetron sputtering target material of target material and back plate mutual binding, comprising the following steps:

[0058] W powder with laser particle size D50=34μm and Ti powder with laser particle size D50=43μm are mixed uniformly according to the component ratio W / Ti 90 / 10wt% by three-dimensional mixer, then are loaded into rubber sleeve and are pressed into a blank by cold isostatic pressing, the machining specification is 120*560*8mm, and the relative density of the pressed blank is 69%. The core mold material is TZM alloy, the outer dimension is 240*240*1120mm, the core mold groove size is 110.5*550.5*5mm, the oxygen-free copper back plate binding surface is plated with a 0.3mm-thick Ni layer, the binding surface plating layer has no exposed part, the core mold outer surface, the inner surface of the package sleeve, and the contact surface between the pressed blank and the core mold are sprayed with 0.3mm-thick alumina, and the sprayed alumina surface has no exposed part, then the back plate binding surface is loaded into the core mold outwardly, the pressed blank is attached to the back plate binding surface, and finally a 4.5mm-thick 20# steel package sleeve is attached and welded. The degassing process is 900℃, time 3h, vacuum degree ≤1×10 -3 Pa. Hot isostatic pressing process is temperature 990℃, time 3h, pressure 130MPa, finally machining to get target material, target material relative density 99.11%, target material and back plate binding surface binding law 99.09%. In this embodiment, the back plate is almost no deformation, the back plate can be reused ≥15 times, the package sleeve is thinned by oxidation about 0.7mm single time, the package sleeve can be reused ≥3 times, which can effectively reduce the production cost.

[0059] Example 4

[0060] This embodiment provides a target material specification is 136*444*8mm, target material material is Cr, back plate specification is 146*454*12.7mm, back plate material is oxygen-free copper, the forming and binding method of magnetron sputtering target material of target material and back plate mutual binding, comprising the following steps:

[0061] Cr powder with laser particle size D50=78 μm is loaded into a rubber sleeve and cold isostatic pressed into a compact, and the compact has a size of 150*460*13 mm and a relative density of 61%, a core mold material is NiW alloy, and an outer size of the core mold is 300*300*920 mm, an oxygen-free copper back plate is pickled and dried, 0.2 mm thick graphite paper is pasted on the outer surface of the core mold, the inner surface of the sleeve and the contact surface between the compact, and the graphite paper surface does not have exposed parts, then the back plate is loaded into the core mold with the binding surface outward, the compact is attached to the binding surface of the back plate, and finally, a 4 mm thick 304 stainless steel sleeve is attached and welded. The degassing process is at a temperature of 540 ℃ for 3 h, a vacuum degree of ≤1*10 -3 Pa, the hot isostatic pressing process is at a temperature of 1100 ℃ for 2 h, a pressure of 135 MPa, and finally, the target material is machined, the target material has a relative density of 99.08%, and the target material and the back plate binding surface have a combination of 99.19%. In the embodiment, the back plate has little deformation, the back plate can be reused for ≥15 times, the sleeve is thinned by about 0.2 mm after single oxidation, the sleeve can be reused for ≥7 times, and the production cost can be effectively reduced.

[0062] The above is only the best specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or substitutions within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

[0063] The contents not described in detail in the specification of the present application belong to the known technology of the person skilled in the art.

Claims

1. A low-cost target forming and bonding method, characterized in that... include: The original target powder is pressed into a compact; Prepare a core mold, and pre-fabricate a fixing groove on the outer surface of the core mold that matches the size of the back plate; pre-fabricate an isolation layer on the outer surface of the core mold, the inner surface of the sleeve, and the contact surface between the pressed blanks; The back plate is installed in the fixing groove of the core mold, the core mold and the outer surface of the back plate are placed with a blank, and the outermost sleeve is installed and welded. The welded sheath is then degassed by heat. The cladding after thermal degassing is then subjected to hot isostatic pressing. After hot isostatic pressing, the weld seam of the cladding is removed and the cladding is taken off. Other materials are removed from the core mold to obtain the target blank. The insulating layer on the target blank is removed and the target blank is then finely machined to obtain the finished target material.

2. The method according to claim 1, characterized in that: The removed casing and used target waste are evaluated to determine if they can be reused. If the evaluation is successful, the casing is flattened, the residual target is removed, and the casing or backing plate is reused.

3. The method according to claim 2, characterized in that: The recycling of the casing is evaluated based on the effective thickness of the casing waste. Aluminum alloy casing waste with an effective thickness ≥ 0.8 mm can be reused, steel casing waste with an effective thickness ≥ 1.2 mm can be reused, and titanium alloy casing waste with an effective thickness ≥ 2 mm can be reused. Backplate recycling is based on the size of the used target waste, i.e., the backplate. If the backplate size is within the dimensional tolerance range, it can be reused.

4. The method according to claim 1, characterized in that, The original powder is a mixture of one or more powders, including single metal powder, single alloy powder, and single compound powder. If two or more powders are mixed, the absolute difference in the laser particle size D50 of different powders is ≤20μm.

5. The method according to claim 1, characterized in that, The compact is prepared by powder molding or cold isostatic pressing, and the relative density of the compact is ≥60%.

6. The method according to claim 1, characterized in that, If a bonding layer is required, a bonding layer is prefabricated on the bonding surface of the backplate before the backplate is installed in the fixing groove of the core mold; the bonding layer is a bonding layer between the target material and the backplate, and the material is a composite layer composed of one or more of copper, nickel and silver, and the bonding layer is prepared by electroplating or spraying.

7. The method according to claim 1, characterized in that, The mandrel is made of a material that does not deform during hot isostatic pressing, and the material selection is matched with the hot isostatic pressing temperature; when the hot isostatic pressing temperature is 300℃~600℃, the mandrel material is selected as heat-resistant steel, molybdenum alloy or tungsten alloy; when the hot isostatic pressing temperature is 600℃~1300℃, the mandrel material is selected as molybdenum alloy or tungsten alloy; when the static pressing temperature is 1300℃~1600℃, the mandrel material is tungsten alloy.

8. The method according to claim 1, characterized in that, The sheath material is matched with the hot isostatic pressing temperature and is made by shearing and bending sheet metal; the hot isostatic pressing temperature is 300℃~600℃ and the sheath material is aluminum alloy; the hot isostatic pressing temperature is 600℃~1300℃ and the sheath material is steel; the static pressing temperature is 1300℃~1600℃ and the sheath material is titanium alloy.

9. The method according to claim 1, characterized in that, The thermal degassing process involves a temperature of 200–1000℃, a time of 2–10 hours, and a vacuum degree ≤1×10⁻⁶. -3 Pa.

10. The method according to claim 1, characterized in that, The hot isostatic pressing process is carried out at a temperature of 300–1600℃ for 1–6 hours and a pressure of 80–200 MPa. After hot isostatic pressing, the relative density of the target material is ≥99%, and the bonding rate between the target material and the backing plate is ≥99%.

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