A low-oxygen high-density low-melting-point target material welding method

Abstract

The application provides a low-oxygen high-density low-melting-point target material welding method, which comprises the following steps: first, machining a welding groove on a back plate and performing roughening treatment; second, placing the treated back plate into a high-temperature-resistant vacuum bag, then placing low-melting-point target material raw materials into the groove of the back plate, vacuumizing, and finally filling inert protective gas and sealing to obtain a welding assembly; third, placing the sealed welding assembly on a brazing table and heating to a molten state of the target material raw materials; fourth, cooling to a semi-solid state of the target material raw materials, then vacuumizing the inert gas in the high-temperature-resistant vacuum bag to a vacuum state; and fifth, taking out after cooling to room temperature, and performing mechanical processing to obtain a finished target material. The method avoids the oxidation and overlapping skin defects caused by direct melting and welding of the low-melting-point target material raw materials, and the welding rate is reduced due to oxidation, so that the production efficiency and the forming and welding quality can be greatly improved, and the welding rate can reach more than 99%.

Description

Technical Field

[0001] This invention relates to the field of target manufacturing technology in magnetron sputtering, and particularly to a method for welding low-oxygen, high-density, low-melting-point targets. Background Technology

[0002] Conventional target materials are typically soldered to the backplate using solder with a melting point lower than that of the target material. However, low-melting-point targets, due to their inherently low melting point, make it difficult to select suitable solders. For example, indium has a melting point of only 156.6℃, and the selected SnIn solder will react with indium, "melting" the indium target. The soldering rate is usually below 90%, and it may even cause soldering failure. Similarly, using indium solder with tin targets will also react with tin, melting the tin target. For targets that are difficult to braze, another welding method is adhesive bonding. However, conductive adhesives are generally hard, making it difficult to control the weld thickness. Excessive weld layer thickness reduces the target surface thickness, thus reducing the target life. At the same time, adhesive bonding cannot be detached. If the welding rate is not up to standard, it is difficult to rework and re-weld, resulting in scrapped targets and extremely high costs. For low-melting-point targets, another welding method is direct melting welding, in which the material is placed in a melting furnace crucible, heated and melted, and then directly cast into a backing plate for solidification. However, this method is prone to secondary contamination of the material due to melting in the crucible, and direct casting and solidification are prone to internal defects and low density. Furthermore, the processing using a melting furnace is costly, time-consuming, and inefficient. Therefore, a low-cost welding method with a high weld success rate is urgently needed for welding such low-melting-point materials. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a low-cost, high-weld-ratio welding method for low-oxygen, high-density, low-melting-point target materials.

[0004] To solve the above-mentioned technical problems, the present invention provides a method for welding low-oxygen, high-density, low-melting-point target materials, comprising:

[0005] The first step is to machine welding grooves on the back plate and roughen it.

[0006] The second step is to put the processed backplate into a high-temperature resistant vacuum bag, then put the low-melting-point target material into the groove of the backplate and evacuate it. Finally, fill it with inert protective gas and seal it to obtain the welded assembly.

[0007] The third step is to weld the target material into shape in one go. After sealing, the welding assembly is placed on the brazing table and heated until the target material material is completely melted in the groove of the back plate to form a molten pool.

[0008] The fourth step is to cool the target material until it becomes a semi-solid state, and then extract the inert gas from the high-temperature vacuum bag to a vacuum state.

[0009] The fifth step is to remove the material after it has cooled to room temperature and then perform machining to obtain the finished target material.

[0010] In the first step, the back plate groove includes the target surface portion of the actual finished target material, the groove depth is greater than the finished target surface thickness, and the groove diameter is greater than the target surface diameter.

[0011] The roughening process in the first step can be achieved by methods such as sandblasting, shot peening, electrical discharge machining, and laser treatment to improve the surface roughness of the groove.

[0012] In the second step, the volume of the low-melting-point target material is greater than the volume of the groove. The material is added once and placed within 1 / 2 radius of the groove in the back plate. After melting, it is continuously spread outward until it fills the entire groove in the back plate.

[0013] In the second step, the high-temperature resistant vacuum bag is a vacuum bag made of materials such as polyimide that can withstand temperatures above 400°C.

[0014] In the second step, the inert gas is argon, nitrogen, or helium. The amount of gas filled is such that the vacuum bag bulges out and the groove on the back plate is completely unobstructed.

[0015] In the third step, the brazing station is set to a temperature of (T+5)℃~(T+100)℃, where T refers to the melting point of the target material.

[0016] In the third step, the molten pool is full, and the upper surface of the molten pool is higher than the back plate surface, forming an arc shape.

[0017] In the fourth step, the semi-solidification temperature is set to (T-40)℃~(T-10)℃, where T refers to the melting point of the target material.

[0018] In the fifth step, the finished target material back plate is in the shape of a boss, and the welding surface is higher than the back plate flange surface.

[0019] Beneficial effects of the present invention

[0020] The low-oxygen, high-density, low-melting-point target welding method provided by this invention is simple and low-cost. It avoids the oxide scale defects caused by direct melting and welding of low-melting-point target materials, as well as the decrease in weld rate due to oxidation. This significantly improves production efficiency and forming and welding quality, achieving a weld rate of over 99%. It effectively solves the problems of complex processing and low weld rate of low-melting-point target materials. Furthermore, the target surface and backing plate are fully filled without gaps, effectively avoiding the problem of water ingress into the brazed target weld seam, which leads to multiple rework and drying processes. Detailed Implementation

[0021] The following examples illustrate the implementation of the present invention in detail, thereby enabling a full understanding and implementation of how the present invention uses technical means to solve technical problems and achieve technical effects.

[0022] Example 1

[0023] The first step is to process the back panel, which involves machining welding grooves on the back panel and then sandblasting the grooves.

[0024] The second step is to place the backing plate inside a high-temperature resistant vacuum bag, then place the indium ingot within half the radius of the groove in the backing plate, ensuring that it can fill the entire groove after melting. The vacuum bag is then evacuated, and high-purity argon gas is filled into the sealed bag to make the vacuum bag partially bulge, ensuring that it does not obstruct the groove of the backing plate.

[0025] The third step is to perform one-time molding and welding of the target material: Set the brazing station temperature to 180℃, place the entire component on the brazing station for heating, and molten the indium ingot to fill the entire backplate groove. Then, change the brazing station temperature setting to 140℃, and after the indium material solidifies, extract the gas from the bag to a vacuum state, turn off the heating power of the brazing station, and continue to cool to room temperature to complete the one-time molding and welding.

[0026] The fourth step is to perform machining to obtain the finished indium target.

[0027] Example 2

[0028] The first step is to process the back panel, which involves machining welding grooves on the back panel and then sandblasting the grooves.

[0029] The second step involves placing the backplate inside a high-temperature resistant vacuum bag, then placing the tin ingot within half the radius of the groove on the backplate, ensuring it fills the entire groove after melting. The vacuum bag is then evacuated and filled with high-purity argon gas to create a partial bulge, ensuring no obstruction of the backplate groove.

[0030] The third step is to perform one-time molding and welding of the target material: Set the brazing station temperature to 250℃, place the entire component on the brazing station for heating, and melt the solder ingot to fill the entire backplate groove. Then, change the brazing station temperature setting to 220℃, and after the solder solidifies, extract the gas from the bag to a vacuum state, turn off the brazing station heating power, and continue to cool to room temperature to complete the one-time molding and welding.

[0031] The fourth step is to perform machining to obtain the finished tin target.

[0032] Comparative Example 1

[0033] The first step is to process the back panel. The welding surface of the back panel is flat, so there is no need to process grooves.

[0034] The second step is to roll the high-purity indium ingot to the target size using the "cross rolling" method.

[0035] The third step is to process the rolled indium target billet to the welding dimensions.

[0036] The fourth step is to weld the target material to the backplate: set the welding table temperature to 130℃, melt a certain amount of SnIn solder on the welding surfaces of the backplate and the target, and ultrasonically wet it. After bonding, take it out and place it on a room temperature table to cool.

[0037] The fifth step is to perform machining to obtain the finished indium target.

[0038] Comparative Example 2

[0039] The first step is to process the back panel. The welding surface of the back panel is flat, so there is no need to process grooves.

[0040] The second step is to roll the high-purity indium ingot to the target size using the "cross rolling" method.

[0041] The third step is to process the rolled indium target billet to the welding dimensions.

[0042] The fourth step is to weld the target to the backplate: set the welding station temperature to 150℃, melt a certain amount of SnIn solder on the welding surface of the backplate and the target, and ultrasonically wet it. Place the indium target on the backplate wetted with SnIn solder for bonding. The SnIn solder melts and erodes the indium target, causing the welding to fail.

[0043] Comparative Example 3

[0044] The first step is to process the back panel. The welding surface of the back panel is flat, so there is no need to process grooves.

[0045] The second step is to roll the high-purity tin ingot to the target size using the "cross rolling" method.

[0046] The third step is to process the rolled tin target blank to the welding dimensions.

[0047] The fourth step is to weld the target to the backplate: set the welding station temperature to 160℃, melt a certain amount of indium solder on the welding surface of the backplate and the target, and ultrasonically wet it. Place the tin target on the backplate wetted with indium solder for bonding. The indium solder melts and erodes the tin target, causing the welding to fail.

[0048] Comparative Example 4

[0049] The first step is to process the back panel. The welding surface of the back panel is flat, so there is no need to process grooves.

[0050] The second step is to roll the high-purity indium ingot to the target size using the "cross rolling" method.

[0051] The third step is to process the rolled indium target billet to the welding dimensions.

[0052] The fourth step is to weld the target to the backplate: apply conductive silver paste to the welding surfaces of the backplate and the indium target respectively, apply it evenly, and then quickly bond it together and let it stand for the conductive silver paste to cure.

[0053] The fifth step is to perform machining to obtain the finished indium target.

[0054] Comparative Example 5

[0055] The first step is to process the back panel, creating welding grooves on it.

[0056] The second step is to perform one-time target forming and welding: Set the welding table temperature to 200℃, place the grooved backplate on the brazing table for preheating, apply a small amount of high-purity indium material after preheating, and ultrasonically impregnate it, then remove the excess indium material. Immediately afterward, melt the high-purity indium ingot into the preheated groove of the backplate, adding the entire ingot at once, placing it within half the radius of the groove to ensure it is completely filled. After the indium ingot has completely melted, remove the backplate and place it on a room-temperature table to cool and solidify.

[0057] The third step is to perform machining to obtain the finished indium target.

[0058] The target preparation and performance results of Examples 1-2 and Comparative Examples 1-5 are shown in Table 1.

[0059] Table 1

[0060] Example 1 none 0 99.93％ Example 2 none 0 99.98％ Comparative Example 1 none <0.1mm 82.14％ Comparative Example 2 / / Indium target erosion, welding failure Comparative Example 3 / / Tin target erosion, soldering failure Comparative Example 4 none 0.5mm 95.32％ Comparative Example 5 Oxidized skin defects 0 96.26％

[0061] All of the foregoing primary implementations of this intellectual property right do not limit other forms of implementation of this new product and / or new method. Those skilled in the art will utilize this important information to modify the foregoing to achieve similar implementations. However, all modifications or alterations based on this new product invention are reserved rights.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for welding low-oxygen, high-density, low-melting-point target materials, characterized in that: include: The first step is to machine welding grooves on the back plate and roughen it. The second step is to put the processed back plate into a high-temperature resistant vacuum bag, then put a low-melting-point target material with a volume larger than the welding groove into the welding groove and then draw a vacuum. Finally, inert protective gas is filled in and sealed to obtain the welding assembly. The amount of inert protective gas filled in is such that the vacuum bag bulges out and the welding groove is completely unobstructed. The third step is to weld the target material into shape in one go. After sealing, the welding assembly is placed on the brazing table and heated until the target material is completely melted in the welding groove to form a molten pool. The temperature of the brazing table is set to (T+5)℃~(T+100)℃, where T refers to the melting point of the target material. The fourth step is to cool the target material to a semi-solid state, with the semi-solid state set at a temperature of (T-40)℃~(T-10)℃. Then, the inert protective gas inside the high-temperature vacuum bag is extracted to a vacuum state. The fifth step is to remove the material after it has cooled to room temperature and then perform machining to obtain the finished target material.

2. The method for welding low-oxygen, high-density, low-melting-point target materials as described in claim 1, characterized in that: In the first step, the depth of the welding groove is greater than the thickness of the finished target surface, and the diameter of the welding groove is greater than the diameter of the target surface.

3. The low-oxygen, high-density, low-melting-point target welding method as described in claim 1, characterized in that: The texturing process in the first step is performed by sandblasting, shot peening, electrical discharge machining, or laser treatment.

4. The method for welding low-oxygen, high-density, low-melting-point target materials as described in claim 1, characterized in that: The high-temperature vacuum bag used in the second step can withstand temperatures above 400°C.

5. The method for welding low-oxygen, high-density, low-melting-point target materials as described in claim 1, characterized in that: In the second step, the inert protective gas is argon, nitrogen, or helium.

6. The method for welding low-oxygen, high-density, low-melting-point target materials as described in claim 1, characterized in that: In the third step, the molten pool is full, and the upper surface of the molten pool is higher than the back plate surface, forming an arc shape.

7. The method for welding low-oxygen, high-density, low-melting-point target materials as described in claim 1, characterized in that: In the fifth step, the finished target material back plate is in the shape of a boss, and the welding surface is higher than the back plate flange surface.