阅读说明：本技术 一种铜靶材组件焊接后焊缝的处理方法及铜靶材组件 (Method for processing welded seam of copper target assembly after welding and copper target assembly ) 是由 姚力军 潘杰 边逸军 王学泽 滕俊 于 2021-09-24 设计创作，主要内容包括：本发明提供一种铜靶材组件焊接后焊缝的处理方法及铜靶材组件,所述处理方法依次通过形成熔融缝、填充熔融缝、堆高至高于边缘平面和平坦化处理,将铜靶材组件与大气接触的焊缝处填平,形成完全密封的孔道,避免了后续溅射过程中对半导体产品造成污染。(The invention provides a method for processing a welded seam of a copper target assembly and the copper target assembly, wherein the method comprises the steps of sequentially forming a melting seam, filling the melting seam, stacking to a position higher than an edge plane and flattening, the welding seam of the copper target assembly contacted with the atmosphere is filled, a completely sealed pore channel is formed, and pollution to a semiconductor product in the subsequent sputtering process is avoided.)

1. A method for processing a welded seam of a copper target assembly after welding is characterized by comprising the following steps:

(1) arranging combustion-supporting substances at a welding seam of the copper target material assembly, which is in contact with the atmosphere, and performing first melting on the welding seam by adopting laser to form a melting seam;

(2) filling a filling material which is the same as the copper target material assembly into the melting seam, performing second melting on the melting seam by using laser, and discharging bubbles in the melting seam to obtain a primary welding part;

(3) continuously arranging a filling material on the surface of the primary processing welding part, and carrying out third melting by adopting laser to obtain a secondary processing welding part with the welding flux higher than the edge plane;

(4) and flattening the secondary treatment welding part to obtain the copper target assembly with the filling part which is flush with the edge plane.

2. The process according to claim 1, wherein the laser intensity of the first melting in the step (1) is 300 to 500W.

3. The process according to claim 1 or 2, characterized in that in step (1) said comburent substance comprises a comburent gum;

preferably, the first molten intermediate weld is welded at a crack between the welds;

preferably, the depth of the fusion seam is 0.2-0.3 mm.

4. The process according to any one of claims 1 to 3, wherein the laser intensity of the second melting in the step (2) is 200 to 300W;

preferably, the diameter of the filling material in the step (2) is 0.1-0.45 mm;

preferably, the number of filling turns of the filling material in the step (2) is 4-5.

5. The process according to any one of claims 1 to 4, wherein the diameter of the filler in the step (3) is 0.1 to 0.45 mm;

preferably, the number of filling turns of the filling material in the step (3) is 4-5;

preferably, the laser intensity of the third melting is 200-300W.

6. The process according to any one of claims 1 to 5, wherein the solder in step (3) is higher than the edge plane by 0.2 to 0.3 mm.

7. The process of any one of claims 1 to 6, wherein after the third melting in step (3), further comprising tapping the solder above the edge plane;

preferably, a protective material is arranged on the knocking surface pad of the copper target assembly in the knocking process;

preferably, the protective material comprises a protective copper sheet.

8. A process according to any one of claims 1 to 7, wherein the planarization in step (4) comprises polishing.

9. A copper target component, which is characterized in that the copper target component is processed by the method for processing the welded seam of the copper target component according to any one of claims 1 to 8.

10. The copper target assembly of claim 9, wherein the copper target assembly comprises a target body and a target backing plate, the target backing plate being welded to the target body by threads;

and a filling part is arranged at a welding seam, which is welded between the target material back plate and the target material main body and is in contact with the atmosphere.

Technical Field

The invention relates to the technical field of semiconductors, in particular to the technical field of target manufacturing, and particularly relates to a method for processing a welded joint of a copper target assembly after welding and the copper target assembly.

Background

The sputtering target material is an important key material necessary for manufacturing a semiconductor chip, and the principle of utilizing the sputtering target material to manufacture a device is to adopt a physical vapor deposition technology and bombard the target material by high-pressure accelerated gaseous ions so as to enable atoms of the target material to be sputtered out and deposited on a silicon wafer in a thin film mode, and finally a complex wiring structure in the semiconductor chip is formed.

The sputtering target has many advantages of uniformity, controllability and the like of metal coating, and is widely applied to the field of semiconductors. Because copper has higher conductivity and better electromigration resistance, copper targets are widely applied to interconnection lines of very large scale integrated circuits at present, and copper sputtering targets become indispensable key materials for development of the semiconductor industry.

Due to the metal characteristics of the copper target material, the welding strength of the copper target material is low when the copper target material is welded with a target material back plate, and therefore, relevant research is conducted on the structure of the copper target material assembly for improving the welding strength of the copper target material.

CN111304604A discloses a diffusion welding method of a copper target and an aluminum alloy back plate and a prepared copper target assembly, wherein the diffusion welding method comprises the following steps: (1) plating a titanium film on the welding surface of the copper target, assembling the copper target plated with the titanium film and the aluminum alloy back plate, and then integrally placing the copper target plated with the titanium film and the aluminum alloy back plate into a jacket; (2) sealing the sheath obtained in the step (1) and then degassing; (3) and (3) carrying out hot isostatic pressing welding on the sheath degassed in the step (2), and then removing the sheath to finish diffusion welding of the copper target and the aluminum alloy backboard. In the diffusion welding method, the aluminum alloy back plate is provided with the threads, so that the firmness of welding and bonding is further improved.

CN212918152U discloses an ultra-high pure copper target welded structure and target subassembly, ultra-high pure copper target welded structure is provided with the screw thread on the face of weld of target backplate to the interval of strict control screw thread is 0.15 ~ 0.25mm, and the degree of depth of screw thread is 0.10 ~ 0.15mm, has improved the size of screw thread on prior art's basis, has improved the welding bonding rate greatly.

CN112122763A discloses a welding method of an ultra-pure copper target and a backing plate, the welding method includes: coating the welding surface of the back plate with the threads, and then assembling the back plate with the ultra-pure copper target; placing the assembled ultra-pure copper target material and the assembled back plate into a sheath, sealing the sheath, and vacuumizing; and carrying out hot isostatic pressing treatment on the vacuumized sheath to complete welding of the ultrahigh-purity copper target and the back plate. According to the method, through the improvement of the structure of the welding surface of the back plate, the thread protrusions can be embedded into the target material, the combination effect of the target material and the back plate is enhanced, the diffusivity of the coating film is utilized, the welding surface of the target material and the welding surface of the back plate are fully covered, the welding combination degree between the target material and the back plate is improved, the welding strength is high, the coating film is arranged on the back plate, the integrity of the coating film during welding is guaranteed, and the damage of the thread protrusions to the coating film is avoided.

However, the applicant has unexpectedly found that the back plate with threads is easy to have wafer contamination during the subsequent sputtering process after being welded with the copper target.

Therefore, there is a need to further improve the process on the basis of the raw weld strength, in view of the problem of wafer contamination during subsequent sputtering.

Disclosure of Invention

In view of the problems in the prior art, the invention provides a method for processing a welding seam after welding of a copper target assembly and the copper target assembly.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a method for processing a welded seam of a copper target assembly after welding, wherein the method for processing the welded seam comprises the following steps:

(1) arranging combustion-supporting substances at a welding seam of the copper target material assembly, which is in contact with the atmosphere, and performing first melting on the welding seam by adopting laser to form a melting seam;

(2) filling a filling material which is the same as the copper target material assembly into the melting seam, performing second melting on the melting seam by using laser, and discharging bubbles in the melting seam to obtain a primary welding part;

(3) continuously arranging a filling material on the surface of the primary processing welding part, and carrying out third melting by adopting laser to obtain a secondary processing welding part with the welding flux higher than the edge plane;

(4) and flattening the secondary treatment welding part to obtain the copper target assembly with the filling part which is flush with the edge plane.

In the production process, in order to solve the problem that the copper target and the target back plate are not welded firmly, the welding strength is obviously improved through the arrangement of the threads, however, no pollution of wafers caused by the target assembly in the subsequent sputtering process is found, the condition that the sputtering process is influenced more than the original welding mode is not found through the research on the subsequent machining and cleaning, after the influence of the welding process is further determined, the influence of the adjustment of the welding process is eliminated, and then the research is carried out in many ways, the inventor finally realizes that the pores exist in the outermost circle after welding caused by the welding of the threaded back plate, and except the obviously visible circle of pores, because the pores are not in a closed state, the small pores on the inner surfaces of the pores caused in the welding process are also exposed in the atmosphere. The existence of the air holes and the pores has no influence on a welding structure and subsequent semiconductor production, however, machining is carried out on the copper target material assembly after welding, the machining comprises rough machining, finish machining, polishing and other procedures, cleaning procedures and the like, machining chips, cleaning liquid and the like generated in the procedures are adsorbed into the air holes and the pores, and the phenomenon is not discovered because the chips, the cleaning liquid and the like adsorbed in the air holes and the pores cannot overflow after being cleaned, but the temperature is extremely high in the sputtering process, and the chips and the cleaning liquid splash out to pollute semiconductor products.

Based on the discovery of the technical problems, the invention develops a method for processing the welded seam after welding in a targeted manner, and the method avoids the mode of welding the welded seam by electron beams and argon arc welding, wherein the problem of infirm welding seam due to the existence of pores at the welded seam in the electron beam welding and has a certain adsorption effect on scraps and cleaning liquid; the argon arc welding has high temperature, so that the properties of the filled material are changed after welding and are different from the original material properties of the copper target assembly, and abnormal phenomena are easy to occur in the sputtering process.

According to the method, firstly, the combustion-supporting substance is used for carrying out first melting, wherein the combustion-supporting substance is beneficial to heat absorption of metal, so that the problem that copper is difficult to melt due to high reflectivity and high thermal conductivity is solved; the first melting forms a melting seam, the depth and the width of the melting seam are larger than those of the original welding seam, conditions are provided for filling sufficient filling materials for the subsequent second melting, and the welding strength of the filling materials and the copper target assembly after the second melting is improved; and the surface of the copper target material component is slightly melted in the first melting process, so that small holes on the surface of the copper target material component are remolded after being melted, and the number of surface pores is reduced.

In the application, the second melting is used for filling enough welding flux in the melting seam, the third melting is used for obtaining a convex part, on one hand, all the melting seams are fully filled, conditions are provided for subsequent flattening, and the filling of the filling material is divided into the second melting and the third melting, so that the strength of the melting welding is improved, and the formation of the welding seam in the melting welding process is reduced.

Preferably, the laser intensity of the first melting in step (1) is 300 to 500W, for example, 300W, 320W, 340W, 360W, 380W, 410W, 430W, 450W, 470W or 500W, but not limited to the values listed, and other values not listed in this range are also applicable.

Preferably, the combustion-supporting substance in step (1) comprises a combustion-supporting gum.

The specific composition of the combustion-supporting adhesive is not particularly limited in the present invention, and any material known to those skilled in the art that can be used for combustion to produce a carbon layer can be used, for example, the material can be universal adhesive 101.

The combustion-supporting substance can be spontaneously combusted under laser, organic components in the combustion-supporting substance generate a carbon layer after being combusted, and the carbon layer is attached to the surface of the target assembly to achieve the effect of reducing the surface reflectivity and the heat conductivity of copper or copper alloy, so that the melting of the copper or copper alloy under the laser intensity of 300-500W can be realized, and the influence of higher-intensity laser on the performance of the target assembly is avoided.

Preferably, the first molten intermediate weld is welded at a crack between the welds.

Preferably, the depth of the melt slit is 0.2 to 0.3mm, and may be, for example, 0.2mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, or 0.3mm, but not limited to the values listed, and other values not listed in this range are also applicable.

Preferably, the fusion seam is arcuate in shape.

Preferably, the laser intensity of the second melting in the step (2) is 200 to 300W, for example, 200W, 210W, 220W, 230W, 240W, 250W, 260W, 270W, 280W or 300W, but not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the filler material in step (2) comprises welding wire.

Preferably, the diameter of the filler in step (2) is 0.1 to 0.45mm, for example, 0.10mm, 0.14mm, 0.18mm, 0.22mm, 0.26mm, 0.3mm, 0.34mm, 0.38mm, 0.42mm, or 0.45mm, but not limited to the above-mentioned values, and other values not listed in this range are also applicable. The diameter of the preferred filling material is in the range, so that the binding force can be ensured, and the complex operation is avoided.

Preferably, the number of filling turns of the filling material in the step (2) is 4-5.

Preferably, the filler material in step (3) comprises welding wire.

Preferably, the diameter of the filler in step (3) is 0.1 to 0.45mm, for example, 0.10mm, 0.14mm, 0.18mm, 0.22mm, 0.26mm, 0.3mm, 0.34mm, 0.38mm, 0.42mm, or 0.45mm, but not limited to the above-mentioned values, and other values not listed in this range are also applicable.

Preferably, the number of filling turns of the filling material in the step (3) is 4-5.

Preferably, the laser intensity of the third melting is 200 to 300W, and may be, for example, 200W, 210W, 220W, 230W, 240W, 250W, 260W, 270W, 280W, 300W, or the like, but is not limited to the values listed, and other values not listed in the range are also applicable.

According to the invention, the laser intensity of the first melting, the second melting and the third melting is preferably the above intensity, wherein the first melting is selected to be 300-500W, which is more beneficial to the melting of combustion-supporting substances and the melting of the target material assembly, and ensures the formation of a melting seam; and only need melt the filler material in second melting and the third melting and slightly melt the target subassembly surface can, the intensity of setting is lower, and the distribution of so intensity can also practice thrift the energy consumption when reaching the solution semiconductor production pollution problem, reduction in production cost.

Preferably, the solder in step (3) is 0.2 to 0.3mm higher than the edge plane, for example, 0.2mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, or 0.3mm, but not limited to the values listed, and other values not listed in this range are also applicable.

Preferably, after the third melting in step (3), knocking the solder higher than the edge plane is further included.

The invention further preferably comprises a knocking step, the whole filling material can generate plastic deformation by knocking the welding flux higher than the edge plane, the filling material can be embedded into the welding line again on the microcosmic aspect, the number of air holes is further reduced, the sealing effect is improved, and the condition of wafer pollution in the subsequent sputtering process is further reduced.

Preferably, a protective material is placed on the strike face pad of the copper target assembly during the strike.

The target assembly is further limited by the protective material, so that the target assembly can be effectively prevented from being damaged in the knocking process.

The material and thickness of the protective material are not particularly limited, and preferably, the protective material comprises a protective copper sheet.

Preferably, the planarization process in step (4) comprises polishing.

Preferably, the material of the target body in the copper target assembly comprises copper or a copper alloy.

Preferably, the material of the target backing plate in the copper target assembly comprises copper or a copper alloy.

The target material main body and the target material back plate are both copper or copper alloy, which is further preferable in the invention, because the combination of the two is easier to generate a welding seam of the outermost ring contacting with the atmosphere in the welding process and is easier to pollute the wafer in the subsequent sputtering process compared with other metals.

In a second aspect, the invention provides a copper target assembly, which is processed by the method for processing a welded seam after welding of the copper target assembly in the first aspect.

Preferably, the copper target assembly comprises a target main body and a target back plate, and the target back plate is welded with the target main body through threads; and a filling part is arranged at a welding seam, which is welded between the target material back plate and the target material main body and is in contact with the atmosphere.

In the copper target assembly provided by the second aspect of the invention, because the air holes and the pores which are in contact with the atmosphere do not exist any more, impurities are not adsorbed any more in the subsequent processing process, so that the overflow of the impurities in the sputtering process does not exist, and the yield of the subsequent semiconductor product is improved.

Preferably, the filling is flush with the edge plane.

The shape of the thread is not limited in the present invention, and any thread known to those skilled in the art for enhancing the welding strength of the target and the backing plate may be used, for example, the thread structure disclosed in CN 212918152U.

Compared with the prior art, the invention has at least the following beneficial effects:

(1) the method for treating the welding seam after welding the copper target assembly fills up the welding seam contacting with the atmosphere, reduces the adsorption condition of impurities in the subsequent processing process, can achieve the effect that air holes with the diameter of less than 0.1mm are less than 9 in the length of 10mm, has less than 3 air holes with the diameter of less than 0.1mm in the length of 10mm under the optimal condition, has the qualification rate of the target assembly aiming at the air holes of more than 85 percent, and can achieve more than 94 percent under the optimal condition;

(2) the copper target assembly provided by the invention has the advantages that impurities do not overflow in the sputtering process, the yield of semiconductor products is improved, the production cost of semiconductors is obviously reduced, and the economic benefit is obvious.

Drawings

Fig. 1 is a schematic view of a welded copper target assembly in a method for processing a welded seam of the copper target assembly according to embodiment 1 of the present invention.

Fig. 2 is a schematic view of the copper target assembly after combustion-supporting substances are set in the method for processing the welded seam of the copper target assembly according to embodiment 1 of the present invention.

Fig. 3 is a schematic view of a first molten copper target assembly in a method for processing a welded seam of the copper target assembly according to embodiment 1 of the present invention.

Fig. 4 is a schematic view of a second molten copper target assembly in the method for processing a welded seam of the copper target assembly according to embodiment 1 of the present invention.

Fig. 5 is a schematic view of a third molten copper target assembly in the method for processing a welded seam of the copper target assembly according to embodiment 1 of the present invention.

Fig. 6 is a schematic view of a copper target assembly after planarization in a method for processing a welded seam of the copper target assembly according to embodiment 1 of the present invention.

In the figure: 1. a target material main body; 2. a target backing plate; 21. a thread; 3. welding seams; 4. a combustion-supporting material; 5. a fusion seam; 6. primarily processing a welding part; 7. performing secondary treatment on the welding part; 8. and a filling part.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

The present invention is described in further detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.

It is to be understood that in the description of the present invention, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

It should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

Example 1

The embodiment provides a method for processing a welded seam 3 of a copper target assembly after welding, which comprises the following steps:

(1) as shown in fig. 1, the welded copper target assembly (copper TU1 target-copper TU1 target backing plate 2) includes a target body 1 and a target backing plate 2, wherein the target backing plate 2 is welded to the target body 1 by a thread 21; the welding seam 3 contacted with the atmosphere is arranged on the outer side of the target material back plate 2 welded with the target material main body 1;

as shown in fig. 2, a combustion-supporting substance 4 (universal glue 101) is arranged at a welding seam 3 where the welded copper target assembly is in contact with the atmosphere, 400W laser is adopted to carry out first melting on the welding seam 3, and as shown in fig. 3, an arc-shaped melting seam 5 with the depth of 0.3mm is formed;

(2) filling a filling material (namely a copper welding wire with the diameter of 0.3mm and 34 circles around a welding seam of the copper target assembly) which is made of the same material as the copper target assembly into the fusion seam 5, performing second fusion on the fusion seam 5 by adopting 250W laser, and discharging bubbles in the fusion seam 5 to obtain a primary processing welding part 6 as shown in FIG. 4;

(3) continuously arranging a filling material (namely a copper welding wire with the diameter of 0.3mm and winding 35 circles of a welding seam of a copper target assembly) on the surface of the primary processing welding part 6, and performing third melting by adopting 300W laser, and obtaining a secondary processing welding part 7 (with the height of 0.2mm) with the welding flux higher than the edge plane as shown in figure 5;

padding a copper sheet on a knocking surface (the side surface where the welding seam 3 is located) of the copper target material assembly, knocking the secondary treatment welding part 7 higher than the edge plane, so that the filling material generates plastic deformation, and the filling material can be embedded into the welding seam 3 again;

(4) and polishing and flattening the secondary treatment welding part 7 to obtain a copper target assembly with a filling part flush with the edge plane as shown in fig. 6, wherein a filling part 8 is arranged at a welding seam 3 which is in contact with the atmosphere and is welded between the target back plate 2 and the target main body 1 in the copper target assembly with the filling part flush with the edge plane, and the filling part 8 is flush with the edge plane.

Example 2

The embodiment provides a method for processing a welded seam of a copper target assembly after welding, which comprises the following steps:

(1) the welded copper target assembly (copper T2 target-copper CuP target back plate) comprises a target main body and a target back plate, wherein the target back plate is welded with the target main body through threads; the outer side of the target material back plate welded with the target material main body is provided with a welding seam contacted with the atmosphere;

arranging a combustion-supporting substance (universal glue 520) at a welding seam, which is in contact with the atmosphere, of the welded copper target assembly, and performing first melting on the welding seam by adopting 500W laser to form a melting seam with the arc depth of 0.25 mm;

(2) filling a filling material (namely a copper welding wire with the diameter of 0.2mm and 5 circles around a welding seam of the copper target assembly) which is made of the same material as the copper target assembly into the melting seam, performing second melting on the melting seam by adopting 300W laser, and discharging bubbles in the melting seam to obtain a primary-treatment welding part;

(3) continuously arranging a filling material (namely a copper welding wire with the diameter of 0.3mm and winding 4 circles around a welding seam of the copper target assembly) on the surface of the primary processing welding part, and performing third melting by adopting 250W laser to obtain a secondary processing welding part (with the welding flux higher than the edge plane by 0.3 mm);

padding a copper sheet on a knocking surface (the side surface where the welding seam is located) of the copper target material assembly, knocking the secondary treatment welding part higher than the edge plane, so that the filling material generates plastic deformation, and the filling material can be embedded into the welding seam again;

(4) and flattening the secondary treatment welding part by polishing to obtain a copper target assembly with a filling part flush with the edge plane, wherein the filling part is arranged at the welding joint, which is in contact with the atmosphere and is welded between the target back plate and the target main body, of the copper target assembly with the filling part flush with the edge plane, and the filling part is flush with the edge plane.

Example 3

The embodiment provides a method for processing a welded seam of a copper target assembly after welding, which comprises the following steps:

(1) the welded copper target assembly (copper T2 target-copper T3 target back plate) comprises a target main body and a target back plate, wherein the target back plate is welded with the target main body through threads; the outer side of the target material back plate welded with the target material main body is provided with a welding seam contacted with the atmosphere;

arranging a combustion-supporting substance (universal glue 101) at a welding seam, which is in contact with the atmosphere, of the welded copper target material assembly, and performing first melting on the welding seam by adopting 300W laser to form a melting seam with the arc depth of 0.2 mm;

(2) filling a filling material (namely a copper welding wire with the diameter of 0.1mm and 5 circles around a welding seam of the copper target assembly) which is made of the same material as the copper target assembly into the melting seam, performing second melting on the melting seam by adopting 200W laser, and discharging bubbles in the melting seam to obtain a primary-treatment welding part;

(3) continuously arranging a filling material (namely a copper welding wire with the diameter of 0.45mm and winding 4 circles around a welding seam of the copper target assembly) on the surface of the primary processing welding part, and performing third melting by adopting 200W laser to obtain a secondary processing welding part (with the welding flux higher than the edge plane by 0.3 mm);

padding a copper sheet on a knocking surface (the side surface where the welding seam is located) of the copper target material assembly, knocking the secondary treatment welding part higher than the edge plane, so that the filling material generates plastic deformation, and the filling material can be embedded into the welding seam again;

(4) and flattening the secondary treatment welding part by polishing to obtain a copper target assembly with a filling part flush with the edge plane, wherein the filling part is arranged at the welding joint, which is in contact with the atmosphere and is welded between the target back plate and the target main body, of the copper target assembly with the filling part flush with the edge plane, and the filling part is flush with the edge plane.

Example 4

The present example provides a method for processing a welded seam of a copper target assembly after welding, which is the same as that of example 1 except that the knocking in step (3) is not performed.

Example 5

The embodiment provides a method for processing a welded joint of a copper target assembly after welding, which is the same as that in embodiment 1 except that the depth of a fusion joint is 0.1 mm.

Example 6

The embodiment provides a method for processing a welded joint of a copper target assembly after welding, which is the same as the embodiment 1 except that the depth of a fusion joint is 0.5 mm.

Comparative example 1

The comparative example provides a method for treating a welded joint of a copper target assembly, which is the same as that in example 1 except that the step (1) is not performed, and the step (2) and the step (3) are directly performed for fusion welding.

Comparative example 2

The comparative example provides a method for treating a welded joint of a copper target assembly, which is the same as that in example 1 except that the step (2) and the step (3) are combined into one melting. The method specifically comprises the following steps:

(1) the welded copper target assembly (copper TU1 target-copper TU1 target back plate) comprises a target main body and a target back plate, wherein the target back plate is welded with the target main body through threads; the outer side of the target material back plate welded with the target material main body is provided with a welding seam contacted with the atmosphere;

arranging a combustion-supporting substance (universal glue 101) at a welding seam, which is in contact with the atmosphere, of the welded copper target assembly, and performing first melting on the welding seam by adopting 400W laser, so as to form a melting seam with the arc depth of 0.3mm as shown in figure 3;

(2) filling a filling material (namely a copper welding wire with the diameter of 0.3mm and 9 circles around a welding seam of the copper target assembly) which is made of the same material as the copper target assembly into the melting seam, and performing second melting on the melting seam by adopting 300W laser to obtain a secondary treatment welding part (with the welding flux higher than the edge plane by 0.2 mm);

padding a copper sheet on a knocking surface (the side surface where the welding seam is located) of the copper target material assembly, knocking the secondary treatment welding part higher than the edge plane, so that the filling material generates plastic deformation, and the filling material can be embedded into the welding seam again;

(3) and flattening the secondary treatment welding part by polishing to obtain a copper target assembly with a filling part flush with the edge plane, wherein the filling part is arranged at the welding joint, which is in contact with the atmosphere and is welded between the target back plate and the target main body, of the copper target assembly with the filling part flush with the edge plane, and the filling part is flush with the edge plane.

Comparative example 3

The comparative example provides a method for processing a welding seam after welding of a copper target assembly, and the method adopts a 2000 kilowatt electron beam welding mode to make up the welding seam, and the distance between every two adjacent welding seams is 2 mm.

Comparative example 4

The comparative example provides a method for processing a welding seam after welding of a copper target assembly, and the method adopts 1600 kilowatt argon arc welding to make up the welding seam.

And the distribution condition of the air holes is judged by adopting a counting mode, and the quantity of the air holes distributed in each 10mm length is measured; meanwhile, the processed target material assembly is subjected to water pressure detection, namely, gas is introduced, whether bubbles exist is observed underwater, if no bubbles exist, the target material assembly is judged to be qualified, the wafer cannot be polluted subsequently, and the result is shown in table 1.

TABLE 1

	Pore distribution	Of target assembliesPercent of pass
			Example 1	2-3 pores with diameter of less than 0.1mm	95.0％
Example 2	2-3 pores with diameter of less than 0.1mm	94.8％
			Example 3	1-2 pores with diameter of less than 0.1mm	95.3％
Example 4	5-6 air holes with diameter less than 0.1mm	89.3％
			Example 5	8-9 air holes with diameter less than 0.1mm	85.3％
Example 6	3-4 pores with diameter less than 0.1mm	90.2％
			Comparative example 1	10-20 air holes with diameter less than 0.1mm	78.1％
Comparative example 2	10-25 air holes with diameter less than 0.1mm	75.6％
			Comparative example 3	5-10 pores with diameter of 0.5mm or more	53％
Comparative example 4	10-30 air holes with diameter less than 0.1mm	72％

From table 1, the following points can be seen:

(1) it can be seen from the comprehensive examples 1 to 6 that the method for processing the welding seam after the copper target assembly is welded provided by the invention obviously reduces the number of air holes, can achieve the effect that the air holes with the diameter of less than 0.1mm are less than 9 air holes within the length of 10mm, and has the target assembly qualification rate aiming at the air holes of more than 85%;

(2) it can be seen from the combination of the example 1 and the comparative examples 1 to 2 that, in the example 1, the first melting is set to generate the melting seam, and the second melting and the third melting are respectively used for two welding, compared with the case that the melting seam is not manufactured in advance in the comparative example 1, and the two-step melting welding is not performed in the comparative example 2, the number of pores below 0.1mm in the length of 10mm in the example 1 is only 2 to 3, the yield of the target assembly is 95.0%, and the number of pores below 0.1mm in the comparative examples 1 to 2 is respectively 10 to 20 and 10 to 25, and the yield is only 78.1% and 75.6%, respectively, thereby showing that the invention significantly reduces the pores in the welding seam of the target through the setting of each step, thereby reducing the adsorption degree of pollutants and the cleaning liquid;

(3) it can be seen from the comprehensive examples 1 and the comparative examples 3 to 4 that the laser welding mode is adopted, compared with the electron beam welding and the argon arc welding adopted in the comparative examples 3 to 4, the number of the air holes below 0.1mm in the length of 10mm in the example 1 is only 2 to 3, the qualification rate of the target assembly is 95.0 percent, the size of the air holes in the comparative example 3 can reach more than 0.5mm, the detected qualification rate is only 53 percent, the number of the air holes below 0.1mm in the comparative example 4 can reach 10 to 30, and the qualification rate is only 72 percent, so that the method disclosed by the invention can be used for making up the welding line through special laser welding, the number of the air holes at the welding line is obviously reduced, and the qualification rate of the target assembly is improved;

(4) as can be seen from the combination of the embodiment 1 and the embodiment 4, the knocking treatment is performed after the third melting in the embodiment 1, compared with the case that the knocking treatment is not performed in the embodiment 4, the number of the pores is increased, and the qualified rate of the pores is increased from 89.3% to 95.0%, thereby showing that the secondary treatment welding part is plastically deformed through the knocking step, so that the filling material further penetrates into the pores to perform the function of refilling and compensating the pores, and the porosity is reduced;

(5) it can be seen from the combination of examples 1 and 5 to 6 that the depth of the melting seam in example 1 is 0.3mm, and compared with the depths of 0.1mm and 0.5mm in examples 5 to 6, the depth of the melting seam in example 5 is relatively shallow, so that it is difficult to achieve sufficient contact and filling between the solder and the target assembly in the subsequent second melting process, and finally 8 to 9 pores below 0.1mm are formed, and the yield of soldering is only 85.3%, in the embodiment 6, although the depth is enough to support the filling of enough filling materials, the depth is too deep, so that the welding seam which is not originally contacted with the atmosphere is communicated, a large number of new air holes are exposed, the number of the air holes with the diameter of less than 0.1mm reaches 3-4, the qualification rate is reduced to 90.2%, the welding time and the material cost of the welding wire are increased, it is thus shown that the present invention significantly reduces the number of air holes by controlling the depth of the melt slit within a specific range.

In summary, the method for processing the welded seam of the copper target assembly and the copper target assembly fill and level the welded seam of the copper target assembly in contact with the atmosphere to form a completely sealed pore channel, thereby avoiding pollution to semiconductor products in the subsequent sputtering process.

The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must be implemented depending on the above detailed structural features. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of selected components of the present invention, additions of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.