CN111618471A - Welding structure and welding method for ultrahigh pure copper target - Google Patents

Abstract

The invention provides an ultrahigh pure copper target welding structure and a welding method, wherein threads are arranged on a welding surface of a target back plate, the distance between the threads is strictly controlled to be 0.15-0.25 mm, and the depth of the threads is controlled to be 0.10-0.15 mm.

Description

Welding structure and welding method for ultrahigh pure copper target

Technical Field

The invention relates to the technical field of semiconductors, in particular to the technical field of ultra-high pure copper targets, and particularly relates to an ultra-high pure copper target welding structure and a welding method.

Background

With the rapid development of very large scale integrated circuits, the size of chips for semiconductors has been reduced to nanometer level, RC delay and electromigration of metal interconnects have become major factors affecting the performance of chips, and conventional aluminum and aluminum alloy interconnects have not been able to meet the requirements of process of very large scale integrated circuits. Compared with aluminum, copper has higher electromigration resistance and higher conductivity, especially ultra-high-purity copper (the purity is more than or equal to 6N), and has important significance for reducing the resistance of a chip interconnection line and improving the operation speed of the chip interconnection line.

The ultra-high pure copper target material is a commonly used lead manufacturing material for manufacturing semiconductor chips due to the excellent electric conductivity, and needs to be welded with another copper alloy backboard material with relatively high strength due to the low hardness (60-65 HV) on one hand and the relatively high cost on the other hand. The copper alloy back plate plays a supporting role on a sputtering machine platform on one hand, and also has excellent heat conduction and electric conduction effects on the other hand. Because the recrystallization temperature of the ultra-high pure copper is low, crystal grains are easy to grow under high temperature and high pressure, thereby generating adverse effects on the line width and uniformity of the wafer. And high pressure is a sufficient condition for ensuring welding quality, so that the ultra-high pure copper target (Blank) and the copper alloy Back Plate (BP) need to be welded at low temperature (less than or equal to 300 ℃) and high pressure (more than or equal to 100 MPa). In order to realize excellent welding of the ultra-high pure copper target and the copper alloy back plate at low temperature, hot isostatic pressing diffusion welding with relatively mature technology is adopted at present. In order to ensure the assembly precision and welding strength of the ultra-high pure copper and the copper alloy back plate, on one hand, aluminum alloy is selected as a sheathing material; on the other hand, threads were turned on the copper alloy backing plate. Since the ultra-high pure copper target (Blank) and the copper alloy Backing Plate (BP) do not form a metallurgical bond but are mechanically connected at the low temperature and high pressure, the thread size is very important for the welding quality of the ultra-high pure copper target.

CN111155059A discloses a target assembly and a manufacturing method thereof, which improves the welding effect by providing threads on the target backing plate or the target welding surface, but does not specifically improve the copper target backing plate with thicker hardness.

CN110539067A discloses a diffusion welding method for high-purity copper target, which increases the welding bonding rate of the target and the backing plate by uniformly arranging metal powder on the welding surface, but the method cannot ensure the uniformity of the sputtering rate of the target, and may cause abnormal phenomena in the subsequent sputtering process of the target.

CN111001921A discloses a diffusion welding method of an ultra-high-purity copper target, wherein the method sets the pitch of threads to be 0.35-0.45 mm and the depth to be 0.2-0.3 mm, and copper powder is added in an auxiliary manner, so that the welding rate is improved, but the problem of uneven sputtering also exists in the process of adding the copper powder.

Therefore, the problem of welding quality of the ultra-high-purity copper target (Blank) and the copper alloy Back Plate (BP) at low temperature and high pressure needs to be solved, and the welding strength of the product is ensured to meet the requirement, so that the target is ensured to be safe and reliable in the sputtering process.

Disclosure of Invention

In view of the problems in the prior art, the invention provides an ultrahigh pure copper target welding structure and a welding method, wherein the welding structure strictly controls the pitch of the threads to be 0.15-0.25 mm, and the depth of the threads to be 0.10-0.15 mm, compared with the original thread size, copper powder is not required to be added, the welding combination effect is greatly improved, the conductivity of a target component is improved finally, the thread size is matched with the angle of the sharp corner of the thread tooth tip and the surface roughness of a welding surface, the welding and matching of a target back plate and an ultrahigh pure copper target are facilitated, the welding effect is further improved, and the welding effect of the ultrahigh pure copper target can be ensured under high pressure and low temperature.

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

in a first aspect, the invention provides an ultra-high pure copper target welding structure, which comprises an ultra-high pure copper target and a target back plate welded with the ultra-high pure copper target; the target material back plate comprises a welding surface, and threads are arranged on the welding surface; the pitch of the threads is 0.15-0.25 mm, and the depth of the threads is 0.10-0.15 mm.

The welding structure strictly controls the pitch of the threads to be 0.15-0.25 mm and the depth of the threads to be 0.10-0.15 mm, compared with the original thread size, the welding structure not only reduces the tooth pitch and improves the welding contact area, but also breaks through the idea that the deeper the original matching depth is, the better the effect is, the shallower the depth is selected, and the welding combination rate is greatly improved.

The pitch of the thread in the present invention is 0.15 to 0.25mm, and may be, for example, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.22mm, 0.23mm, 0.24mm, or 0.25 mm.

The depth of the thread is 0.10 to 0.15mm, and may be, for example, 0.10mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, or 0.15 mm.

Preferably, the copper purity of the ultra-high purity copper target material is more than or equal to 6N, and can be 99.9999 wt%, 99.99991 wt%, 99.99992 wt%, 99.99994 wt% or 99.99995 wt%, for example.

Preferably, the target backing plate is a copper alloy backing plate.

Preferably, the copper alloy back-sheet comprises a CuZn alloy back-sheet or a CuCr alloy back-sheet.

Preferably, the thread is a castellated thread.

Preferably, the angle of the sharp point of the tooth tip of the toothed thread is 55 ° or 60 °.

According to the invention, the sharp angle of the tooth tip is strictly controlled on the basis that the pitch of the threads is 0.15-0.25 mm and the depth of the threads is 0.10-0.15 mm, so that the matching of the target material back plate and the ultra-high pure copper is facilitated, the situations of tooth tip bending and the like are avoided, and the welding bonding rate is better improved.

Preferably, the roughness of the welding surface of the target backing plate is less than or equal to 0.8 μm, and may be, for example, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.45 μm, 0.4 μm, 0.35 μm, 0.3 μm, 0.25 μm, or 0.2 μm.

The roughness of the welding surface is controlled simultaneously in the invention, so that the welding surface is combined more tightly.

In a second aspect, the present invention provides a welding method for an ultra-high pure copper target, where the welding method uses the ultra-high pure copper target welding structure of the first aspect to perform welding.

Preferably, the welding method comprises the steps of:

(1) after the welding surface of the target backboard is pretreated, assembling and vacuum packaging the target backboard and the ultra-high pure copper target to obtain a packaged target assembly;

(2) and (2) sequentially carrying out sheath welding and hot isostatic pressing welding on the target assembly in the step (1) to obtain a welded target assembly.

The welding structure is combined with sheath welding and hot isostatic pressing welding, and the welded target assembly is not easy to have abnormal phenomena in the sputtering process.

Preferably, the pretreatment in the step (1) includes rust removal, cleaning and drying which are sequentially performed.

Preferably, the rust removal comprises: and removing rust on the thread surface along the thread turning direction by adopting a steel wire brush.

Preferably, the cleaning comprises ultrasonic cleaning.

Preferably, the ultrasonic cleaning time is 22-28 min, for example, 22min, 23min, 24min, 25min, 26min, 27min or 28 min.

Preferably, the cleaning solution for cleaning comprises isopropyl alcohol.

Preferably, the drying temperature in step (1) is 62 to 75 ℃, for example 62 ℃, 63 ℃, 64 ℃, 65 ℃, 66 ℃, 67 ℃, 68 ℃, 69 ℃, 70 ℃, 72 ℃, 74 ℃ or 75 ℃.

Preferably, the drying time is 65-85 min, such as 65min, 67min, 68min, 69min, 70min, 72min, 75min, 78min, 80min, 82min or 85 min.

Preferably, the drying is performed under vacuum conditions.

Preferably, the degree of vacuum of the drying is less than or equal to 0.01Pa, and may be, for example, 0.01Pa, 0.008Pa, 0.007Pa, 0.005Pa, 0.004Pa, or the like.

Preferably, the vacuum packaging time in step (1) is less than or equal to 5min, such as 5min, 4.5min, 4.2min, 4min, 3.8min or 3.5 min.

The invention strictly controls the time of vacuum packaging to be less than or equal to 5min, and can effectively prevent the ultrahigh pure copper target material from rusting.

Preferably, the sheath welding in the step (2) adopts argon arc welding to weld the sheath.

Preferably, the material of the sheath is an aluminum alloy.

Preferably, the sheath is evacuated after welding.

Preferably, the vacuum degree of the vacuum pumping of the ladle sleeve is less than or equal to 0.001Pa, and can be 0.001Pa, 0.0008Pa, 0.0005Pa and the like, for example.

Preferably, the time interval between the hot isostatic pressing welding and the capsule vacuumizing in the step (2) is less than or equal to 24h, such as 24h, 23h, 22h, 20h, 15h, 12h, 10h, 5h, 3h or 2 h.

The invention controls the time interval between the hot isostatic pressing welding and the vacuum pumping of the sheath, and can better improve the welding effect.

Preferably, the hot isostatic pressing welding temperature is 255 to 272 ℃, and may be 255 ℃, 256 ℃, 258 ℃, 260 ℃, 262 ℃, 265 ℃, 268 ℃, 270 ℃, 272 ℃ or the like, for example.

Preferably, the pressure of the hot isostatic pressing welding is 96 to 105MPa, and may be 96MPa, 98MPa, 99MPa, 100MPa, 101MPa, 102MPa, 103MPa, 104MPa, 105MPa, or the like.

Preferably, the time for the hot isostatic pressing welding is 3.2-4.5 h, for example, 3.2h, 3.3h, 3.4h, 3.5h, 3.8h, 4.0h, 4.2h or 4.5 h.

As a preferred technical scheme of the invention, the method comprises the following steps:

(1) the welding surface of the target backboard is sequentially subjected to rust removal, isopropanol cleaning and drying, the target backboard and the ultra-high pure copper target are assembled and vacuum-packed within 5min, and a packed target assembly is obtained;

(2) and (2) vacuumizing the target assembly in the step (1) through an argon arc welding sheath and a sheath until the vacuum degree is less than or equal to 0.001Pa, performing hot isostatic pressing welding within 24 hours at the temperature of 255-272 ℃, under the pressure of 96-105 MPa for 3.2-4.5 hours, and removing the sheath after the hot isostatic pressing is completed to obtain the welded target assembly.

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

(1) the welding structure of the ultra-high pure copper target provided by the invention simultaneously reduces the thread pitch and the thread depth, improves the welding area, and finally improves the welding effect of the target assembly, and the conductivity of the target assembly after welding is more than or equal to 58.9 MS/m;

(2) the welding structure of the ultra-high pure copper target material provided by the invention optimizes the sharp angle of the tooth-shaped thread and improves the assembly effect of the ultra-high pure copper target material and the target material assembly;

(3) the welding method of the ultra-high pure copper target material provided by the invention integrates the improved welding structure and technological parameters, can obtain the target material assembly which is firmly welded in a low-temperature and high-pressure environment, and effectively avoids the abnormal phenomenon in the subsequent target material sputtering process.

Drawings

Fig. 1 is a schematic view of an ultra-high purity copper target welding structure provided in embodiment 1 of the present invention.

Fig. 2 is a schematic diagram of an ultra-high purity copper target in a capsule in application example 1 of the present invention.

FIG. 3 is an ultrasonic inspection diagram of target assemblies welded according to application examples 1, 4 to 7 and application comparative examples 1 to 3 of the present invention.

In the figure: 1-ultra-high pure copper target material; 2-target backing plate; 31-upper sheath cover plate; 32-lower layer covering cover.

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.

First, examples and comparative examples

Example 1

The present embodiment provides an ultra-high pure copper target welding structure, as shown in fig. 1, the welding structure includes an ultra-high pure copper target 1 and a target backing plate 2 welded to the ultra-high pure copper target; the copper purity of the ultra-high-purity copper target 1 is 99.9999 wt%, and the target backing plate 2 is a CuZn alloy backing plate (Cu content is 61.8 wt%, and Zn content is 36.6 wt%).

The target material back plate 2 comprises a welding surface, and tooth-shaped threads are arranged on the welding surface; the pitch of the threads is 0.15mm, and the depth of the threads is 0.12 mm; the angle of the sharp angle of the thread tooth point is 60 degrees, and the roughness of the welding surface of the target backboard is 0.4 mu m.

Example 2

The embodiment provides an ultra-high pure copper target welding structure, which comprises an ultra-high pure copper target and a target back plate welded with the ultra-high pure copper target; the copper purity of the ultra-high pure copper target is 99.99991 wt%, and the target backing plate is a CuCr alloy backing plate (the Cu content is 96.8 wt%, and the Cr content is 0.5 wt%).

The target material back plate comprises a welding surface, and tooth-shaped threads are arranged on the welding surface; the pitch of the threads is 0.25mm, the depth of the threads is 0.15mm, the angle of the sharp angle of the tooth tip of the threads is 55 degrees, and the roughness of the welding surface of the target back plate is 0.3 mu m.

Example 3

The embodiment provides an ultra-high pure copper target welding structure, which comprises an ultra-high pure copper target and a target back plate welded with the ultra-high pure copper target; the copper purity of the ultra-high pure copper target is 99.99992 wt%, and the target backing plate is a CuCr alloy backing plate (the Cu content is 97.1 wt%, and the Cr content is 0.4 wt%).

The target material back plate comprises a welding surface, and tooth-shaped threads are arranged on the welding surface; the pitch of the threads is 0.15mm, the depth of the threads is 0.10mm, the angle of the sharp angle of the tooth tip of the threads is 55 degrees, and the roughness of the welding surface of the target backing plate is 0.8 mu m.

Example 4

The present embodiment provides an ultra-high purity copper target welded structure, which is the same as that of embodiment 1 except that the roughness of the welded structure is 1.0 μm.

Example 5

The present embodiment provides an ultra-high purity copper target welding structure, which is the same as that of embodiment 1 except that the angle of the sharp corner of the thread tooth tip is 50 °.

Comparative example 1

The comparative example provides an ultra-high purity copper target welded structure, and the welded structure is the same as that of example 1 except that the pitch of the threads is 0.3 mm.

Comparative example 2

The comparative example provides an ultra-high purity copper target welded structure, which is the same as that of example 1 except that the depth of the thread is 0.08 mm.

Comparative example 3

The comparative example provides an ultra-high purity copper target welded structure, which is the same as that of example 1 except that the depth of the thread is 0.20 mm.

Second, application example and application comparative example

Application example 1

The application example provides an ultra-high pure copper target welding method, the method adopts the ultra-high pure copper target welding structure provided by the embodiment 1 to weld, and the method specifically comprises the following steps:

(1) the welding surface of the target material back plate is turned by diamond to form tooth-shaped threads, the distance between every two tooth-shaped threads is 0.15mm, and the depth of each tooth-shaped thread is 0.12 mm; the angle of the sharp angle of the thread tooth tip is 60 degrees, and the roughness of the welding surface of the target backboard is 0.4 mu m;

(2) the welding surface of the target backboard is sequentially subjected to rust removal, isopropanol cleaning and drying, the target backboard and the ultra-high pure copper target are assembled and vacuum-packed within 5min, and a packed target assembly is obtained; wherein the drying is carried out for 85min at 62 ℃ under the vacuum condition of 0.01 Pa;

(3) and (3) after the target assembly is subjected to argon arc welding, a sheath and a sheath are vacuumized until the vacuum degree is 0.001Pa, hot isostatic pressing welding is immediately carried out, the hot isostatic pressing welding temperature is 260 ℃, the pressure is 100MPa, the hot isostatic pressing welding time is 4h, the sheath is removed after the hot isostatic pressing is completed, and the welded target assembly is obtained, wherein the schematic diagram of the target assembly in the sheath is shown in figure 2, the ultra-high purity copper target 1 is arranged above a target backboard 2 and is placed in the sheath, an upper sheath cover plate 31 is arranged at the upper part of the sheath, and a lower sheath cover plate 32 is arranged at the lower part of the sheath.

Application example 2

The application example provides an ultra-high pure copper target welding method, the method adopts the ultra-high pure copper target welding structure provided by the embodiment 2 to weld, and the method specifically comprises the following steps:

(1) processing tooth-shaped threads on the welding surface of the target back plate by diamond turning, wherein the distance between the tooth-shaped threads is 0.25mm, the depth of the tooth-shaped threads is 0.15mm, the angle of the sharp point of the tooth tip of each thread is 55 degrees, and the roughness of the welding surface of the target back plate is 0.3 mu m;

(2) the welding surface of the target backboard is sequentially subjected to rust removal, isopropanol cleaning and drying, the target backboard and the ultra-high pure copper target are assembled and vacuum-packed within 5min, and a packed target assembly is obtained; wherein the drying is carried out for 65min at 75 ℃ under the vacuum condition of 0.008 Pa;

(3) and (3) vacuumizing the target assembly in the step (2) to the vacuum degree of 0.0008Pa through an argon arc welding sheath and a sheath, performing hot isostatic pressing welding within 2h, wherein the hot isostatic pressing welding temperature is 255 ℃, the pressure is 105MPa, and the hot isostatic pressing welding time is 3.5h, removing the sheath after the hot isostatic pressing is completed, and obtaining the welded target assembly.

Application example 3

The application example provides an ultra-high pure copper target welding method, the method adopts the ultra-high pure copper target welding structure provided by the embodiment 3 to weld, and the method specifically comprises the following steps:

(1) processing tooth-shaped threads on the welding surface of the target back plate by diamond turning, wherein the distance between the tooth-shaped threads is 0.15mm, the depth of the tooth-shaped threads is 0.10mm, the angle of the sharp point of the tooth tip of each thread is 55 degrees, and the roughness of the welding surface of the target back plate is 0.8 mu m;

(2) the welding surface of the target backboard is sequentially subjected to rust removal, isopropanol cleaning and drying, the target backboard and the ultra-high pure copper target are assembled and vacuum-packed within 5min, and a packed target assembly is obtained; wherein the drying is drying for 70min at 68 ℃ under the vacuum condition of 0.005 Pa;

(3) and (3) vacuumizing the target assembly in the step (2) to the vacuum degree of 0.0007Pa through an argon arc welding sheath and a sheath, performing hot isostatic pressing welding within 4h at the temperature of 270 ℃ under the pressure of 96MPa for 3.2h, and removing the sheath after the hot isostatic pressing is completed to obtain the welded target assembly.

Application example 4

The application example provides an ultra-high pure copper target welding method, and the method is the same as the application example 1 except that the ultra-high pure copper target welding structure provided in the embodiment 4 is adopted for welding.

Application example 5

The application example provides an ultra-high pure copper target welding method, and the method is the same as the application example 1 except that the ultra-high pure copper target welding structure provided in the embodiment 5 is adopted for welding.

Application example 6

The application example provides an ultra-high purity copper target welding method, and the method is the same as the application example 1 except that the vacuum packaging time in the step (2) is 8 min.

Application example 7

The application example provides a welding method of an ultra-high pure copper target, and the method is the same as the application example 1 except that the hot isostatic pressing welding is carried out 26 hours after the vacuum pumping of a sheath.

Application comparative examples 1 to 3

The application comparative examples 1 to 3 provide an ultra-high pure copper target welding method, and the method is the same as the application example 1 except that the ultra-high pure copper target welding structures provided in the comparative examples 1 to 3 are respectively adopted for welding.

Third, test and results

Carrying out ultrasonic detection on the welded target assemblies in the application examples 1, 4-7 and 1-3, wherein the ultrasonic detection result is shown in fig. 3, wherein A is an ultrasonic detection diagram of the target assembly welded in the application example 1, and B is an ultrasonic detection diagram of the target assembly welded in the application example 4; c represents an ultrasonic detection diagram of the target assembly welded according to application example 5 of the invention; d represents an ultrasonic detection diagram of the target assembly welded according to application example 6 of the invention; e represents an ultrasonic detection diagram of the target material assembly welded according to application example 7 of the invention; f represents an ultrasonic detection image of the target assembly welded by the welding method of the comparative example 1; g represents an ultrasonic detection diagram of the target assembly welded by the method of the invention in the comparative example 2; h represents an ultrasonic inspection of the target assembly welded using comparative example 3 according to the present invention.

As can be seen from a in fig. 3, in application example 1, the ultrasonic detection result is darker in color by strictly controlling the size of the thread structure and the process conditions, which indicates that the welding quality of the ultra-high purity target material is good and the threads are completely engaged.

As can be seen from B in fig. 3, the larger roughness of the welding surface of the backing plate in application example 4 leads to a lighter gray level of the detection result of the welded target assembly, thereby indicating that the roughness of the welding surface is strictly controlled and the engagement effect of the threads is improved.

As can be seen from C in fig. 3, the detection result in application example 5 is inferior to that in application example 1, which indicates that the present invention can effectively prevent thread deformation and improve the welding effect by strictly controlling the angle of the sharp corner of the thread tooth point.

As can be seen from fig. 3D and E, the welding effect is worse than that of the application example 1 due to the fact that the vacuum packaging time in the application example 6 is prolonged and the hot isostatic pressing welding is carried out for more than 24 hours after the vacuum pumping of the ladle sleeve in the application example 7, which shows that the time for vacuum packaging and the time for the gap between the vacuum pumping and the hot isostatic pressing of the ladle sleeve are preferably strictly controlled, so that the oxidation condition of the welding surface of the ultra-high pure copper target material and the copper alloy backboard can be effectively reduced, the thread engagement degree is finally improved, and the welding effect is further improved.

It can be seen from F, G and H in FIG. 3 that the welding effect of the invention is far inferior to that of application example 1 by adjusting the pitch or depth of the threads in comparative examples 1 to 3 beyond the protection scope of the invention, thereby showing that the welding effect of the ultra-high pure copper target material is greatly improved by strictly controlling the pitch and depth of the threads.

Conductivity tests were performed on the ultra-high-purity copper target assemblies welded according to the application examples and the application comparative examples, and the test results are shown in table 1.

TABLE 1

	Conductivity (MS/m)
		Application example 1	60.5
Application example 2	60.4
		Application example 3	59.2
Application example 4	60.1
		Application example 5	58.9
Application example 6	59.4
		Application example 7	59.6
Application comparative example 1	58.6
		Comparative application example 2	58.0
Comparative application example 3	58.2

From table 1, the following points can be seen:

(1) as can be seen from the comprehensive application examples 1-7, in the application examples 1-7, the distance between the threads is controlled to be 0.15-0.25 mm, and the depth of the threads is controlled to be 0.10-0.15 mm, so that the welding effect of the target assembly is excellent, the conductivity of the welded target assembly is not less than 58.9MS/m, and the conductivity is better;

(2) it can be seen from the comprehensive application examples 1 and 4-7 that the roughness of the welding surface of the back plate, the size of the threads, the drying time, the interval time from the package degassing to the hot isostatic pressing welding and other factors have obvious influence on the conductivity of the target material, so that the roughness of the welding surface after further optimization is not more than 0.80 mu m, the angle of the sharp corner of the tooth tip of the thread is 55 degrees or 60 degrees, the time of vacuum packaging is controlled within 5min, and the hot isostatic pressing welding is carried out immediately after the package degassing, so that the welding effect of the target material and the conductivity of the target material assembly after welding are improved;

(3) it can be seen from the comprehensive application example 1 and the application comparative examples 1 to 3 that the pitch of the tooth-shaped threads in the application example 1 is 0.15mm, the depth of the tooth-shaped threads is 0.12mm, and compared with the application comparative examples 1 to 3 in which the pitch of the threads is 0.3mm, the depth of the threads is 0.08mm and the depth of the threads is 0.20mm, the conductivity of the target assembly after welding in the application example 1 is 60.5MS/m, and the conductivities of the target assemblies after welding in the application comparative examples 1 to 3 are only 58.6MS/m, 58.0MS/m and 58.2MS/m, respectively, thereby showing that the welding effect and the conductivity of the target assembly after welding are greatly improved by strictly controlling the size of the tooth-shaped threads.

In conclusion, the welding structure and the welding method of the ultra-high pure copper target provided by the invention have the advantages that the welding combination effect and the conductivity of the target after welding are greatly improved by strictly controlling the size of the threads and assisting in cooperatively controlling the angle of the sharp angle of the tooth tip of the threads, the surface roughness of the welding surface and the welding process, wherein the conductivity of the target assembly after welding is more than or equal to 58.9MS/m, the welding strength of the product can be ensured to meet the requirement, and the target is ensured to be safe and reliable in the 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.

Claims (10)

1. The ultrahigh pure copper target welding structure is characterized by comprising an ultrahigh pure copper target and a target back plate welded with the ultrahigh pure copper target;

the target material back plate comprises a welding surface, and threads are arranged on the welding surface;

the pitch of the threads is 0.15-0.25 mm, and the depth of the threads is 0.10-0.15 mm.

2. The welding structure according to claim 1, wherein the ultra-high purity copper target has a copper purity of 6N or more;

preferably, the target backing plate is a copper alloy backing plate;

preferably, the copper alloy back-sheet comprises a CuZn alloy back-sheet or a CuCr alloy back-sheet;

preferably, the thread is a castellated thread;

preferably, the angle of the sharp angle of the tooth tip of the tooth-shaped thread is 55 degrees or 60 degrees;

preferably, the roughness of the welding surface of the target backing plate is less than or equal to 0.8 μm.

3. A welding method of an ultra-high purity copper target, characterized in that the welding method adopts the ultra-high purity copper target welding structure of claim 1 or 2 for welding.

4. Welding method according to claim 3, characterized in that it comprises the following steps:

(1) after the welding surface of the target backboard is pretreated, assembling and vacuum packaging the target backboard and the ultra-high pure copper target to obtain a packaged target assembly;

(2) and (2) sequentially carrying out sheath welding and hot isostatic pressing welding on the target assembly in the step (1) to obtain a welded target assembly.

5. The welding method according to claim 4, wherein the pretreatment in step (1) includes rust removal, cleaning, and drying which are performed in this order;

preferably, the rust removal comprises: removing rust on the thread surface along the thread turning direction by using a steel wire brush;

preferably, the cleaning comprises ultrasonic cleaning;

preferably, the ultrasonic cleaning time is 22-28 min;

preferably, the cleaning solution for cleaning comprises isopropyl alcohol.

6. The welding method according to claim 5, wherein the temperature of the drying in the step (1) is 62-75 ℃;

preferably, the drying time is 65-85 min;

preferably, the drying is performed under vacuum conditions;

preferably, the vacuum degree of the drying is less than or equal to 0.01 Pa.

7. The welding method according to any one of claims 4 to 6, wherein the time for vacuum packing in step (1) is not more than 5 min.

8. The welding method according to any one of claims 4 to 7, wherein the sheath welding in the step (2) adopts argon arc welding to weld the sheath;

preferably, the material of the sheath is aluminum alloy;

preferably, after the sheath is welded, vacuumizing the sheath;

preferably, the vacuum degree of the package cover vacuumized is less than or equal to 0.001 Pa.

9. The welding method according to any one of claims 4 to 8, wherein the time interval between the hot isostatic pressing welding and the vacuum pumping of the capsule in the step (2) is less than or equal to 24 h;

preferably, the temperature of the hot isostatic pressing welding is 255-272 ℃;

preferably, the pressure of the hot isostatic pressing welding is 96-105 MPa;

preferably, the time for hot isostatic pressing welding is 3.2-4.5 h.

10. Welding method according to any one of claims 3-9, characterized in that the method comprises the steps of:

(1) the welding surface of the target backboard is sequentially subjected to rust removal, isopropanol cleaning and drying, the target backboard and the ultra-high pure copper target are assembled and vacuum-packed within 5min, and a packed target assembly is obtained;

(2) and (2) vacuumizing the target assembly in the step (1) through an argon arc welding sheath and a sheath until the vacuum degree is less than or equal to 0.001Pa, performing hot isostatic pressing welding within 24 hours at the temperature of 255-272 ℃, under the pressure of 96-105 MPa for 3.2-4.5 hours, and removing the sheath after the hot isostatic pressing is completed to obtain the welded target assembly.

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