CN119635060A - A welding method for large-size tungsten-silicon alloy target - Google Patents

Abstract

The invention relates to a welding method of a large-size tungsten-silicon alloy target, which comprises the steps of respectively machining a back plate and the tungsten-silicon target, sequentially and concentrically arranging an assembly groove and a welding groove from top to bottom on the welding surface of the back plate, wherein the diameter of the welding groove is smaller than that of the target to obtain a pretreated back plate and a pretreated target, filling the welding groove of the pretreated back plate with welding materials, coating the welding surface of the pretreated target with the welding materials, heating the back plate and the target to melt the welding materials, respectively carrying out infiltration treatment on the welding surfaces of the back plate and the target to obtain the infiltrated back plate and the target, assembling the infiltrated back plate and the target to obtain a target assembly, carrying out pressurization treatment on the target assembly, and then cooling to obtain the welded target assembly. The welding method provided by the invention can effectively improve the welding bonding strength of the target and the backboard, avoid the target assembly from being unwelded and cracked, and reduce the deformation caused by welding.

Description

Welding method for large-size tungsten-silicon alloy target

Technical Field

The invention relates to the technical field of targets, in particular to a welding method of a large-size tungsten-silicon alloy target.

Background

In the semiconductor field, tungsten silicon targets play an important role and are widely applied to gate materials and barrier layers. The target material needs to be subjected to repeated temperature rise in the sputtering process, so that the target material is required to have good welding strength and lower welding stress when in use, so that the bad problems of desoldering, cracking and the like are avoided, and the stability and the reliability of the semiconductor device are further ensured.

However, tungsten silicon is a hard alloy material, has relatively poor toughness, is extremely easy to crack in the process of uneven cold and hot or deformation, and has great difficulty in welding large-size tungsten silicon targets (the diameter is more than or equal to 420mm and the thickness is less than or equal to 13 mm). Currently, soldering, diffusion welding, and other welding methods have been widely used for manufacturing target assemblies, but these methods still have some limitations. Taking hot isostatic pressing welding as an example, after the hot isostatic pressing welding is finished, the sheath is not easy to remove and is easy to adhere to the target assembly, so that the target assembly is easy to damage.

For example, CN104259644A discloses a tungsten-titanium alloy target welding method comprising first providing a tungsten-titanium alloy target and a copper alloy backing plate, forming an aluminum or aluminum alloy layer on the tungsten-titanium target welding surface, and then connecting the tungsten-titanium alloy target to the copper alloy backing plate by a diffusion welding method. Although the method can obtain the target assembly, the welding strength is difficult to further improve, the preparation method is complex, and the deformation of the target assembly is easy to cause.

Therefore, how to solve the problems of desoldering and cracking in the welding process of large-size tungsten silicon targets, improve the welding strength of target components and reduce the deformation of the target components is a technical problem to be solved in the prior art.

Disclosure of Invention

Compared with the prior art, the welding method provided by the invention can effectively improve the welding bonding strength of the target and the backboard, avoid the target assembly from being unwelded and cracked, and reduce the deformation caused by welding.

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

the invention provides a welding method of a large-size tungsten silicon alloy target, which comprises the following steps of:

(1) Respectively machining a backboard and a tungsten silicon target, wherein an assembly groove and a welding groove are sequentially and concentrically arranged on a welding surface of the backboard from top to bottom, and the diameter of the welding groove is smaller than that of the target, so that a pretreated backboard and a pretreated target are obtained;

(2) Filling the solder in the solder tank of the pretreated backboard obtained in the step (1), coating the solder on the welding surface of the pretreated target material, heating the backboard and the target material to melt the solder, and respectively carrying out infiltration treatment on the welding surfaces of the backboard and the target material to obtain the infiltrated backboard and the target material;

(3) Assembling the infiltrated backboard obtained in the step (2) with the target to obtain a target assembly, performing pressurization treatment on the target assembly, and then cooling to obtain the welded target assembly.

According to the preparation method provided by the invention, the butt joint of the target and the backboard is ensured by arranging the assembly groove and the welding groove, enough welding flux can be filled in the welding groove, and the problem of insufficient welding flux is avoided, so that the welding surface is subjected to sufficient infiltration treatment, the bonding strength of the welding flux and the welding surface is further improved, the welding firmness is enhanced, and then the tiny gaps in the welding process can be effectively eliminated through the pressurizing treatment, so that the welding flux is more fully filled in the welding surface, and the welding strength is further enhanced.

Preferably, the back sheet of step (1) comprises a copper chromium alloy back sheet.

Preferably, the diameter of the tungsten silicon target material in the step (1) is equal to or larger than 420mm, for example, 420mm, 430mm, 440mm or 450mm, but is not limited to the listed values, and other non-listed values in the numerical range are equally applicable.

Preferably, the thickness of the tungsten silicon target material is less than or equal to 13mm, for example, 13mm, 12mm, 11mm or 10mm, but the tungsten silicon target material is not limited to the listed values, and other non-listed values in the numerical range are applicable.

Preferably, after the machining in step (1), the surface roughness Ra of the back plate is 4-8 μm, and may be, for example, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm or 8 μm, but is not limited to the values recited, and other values not recited in the numerical range are equally applicable.

Preferably, after the machining, the surface roughness Ra of the tungsten silicon target is 7-12 μm, for example, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm or 12 μm, but not limited to the recited values, and other non-recited values within the numerical range are equally applicable.

In the invention, the surface roughness of the backboard and the target material is preferably controlled in a specific range, so that the solder can be fully and uniformly wetted on the welding surface, the solder can be better spread and filled in the welding area, the welding defects are reduced, and the welding strength is improved.

Preferably, the difference between the diameter of the solder pot in step (1) and the diameter of the target is 4-6mm, for example, 4mm, 4.5mm, 5mm, 5.5mm or 6mm, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

According to the invention, the difference between the diameter of the welding groove and the diameter of the target is preferably controlled within a specific range, so that the overflow of the welding flux in the welding process can be effectively prevented, the welding flux is ensured to be uniformly distributed in the welding process, the proper contact area of the welding flux with the target and the backboard is ensured, and the welding strength is ensured.

Preferably, the depth of the solder bath is 2-4mm, and may be, for example, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, or 4mm, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

According to the invention, proper filling of solder in the welding process can be ensured by preferably controlling the depth of the solder tank, and the solder in the solder tank is introduced into the welding surface of the backboard during the infiltration treatment, so that the welding strength is improved, the phenomenon that the solder escapes due to excessive filling of the solder, the welding defect is generated, the welding quality is influenced, and meanwhile, the phenomenon that the welding gap cannot be filled due to insufficient filling of the solder is avoided, and the influence on the firmness and reliability of welding is avoided.

Preferably, the solder of step (2) comprises indium solder.

Preferably, the heating rate is 10 ℃ or less per minute, for example, 10 ℃, 9 ℃,8 ℃,7 ℃,6 ℃,5 ℃,4 ℃,3 ℃,2 ℃ or 1 ℃ per minute, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the end temperature of the heating is 190-230 ℃, which may be, for example, 190 ℃, 195 ℃, 200 ℃, 205 ℃, 210 ℃, 215 ℃, 220 ℃, 225 ℃ or 230 ℃, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the infiltration treatment of step (2) is performed under ultrasonic conditions.

Preferably, the ultrasonic wave has a frequency of 15-25kHz, and may be, for example, 15kHz, 16kHz, 17kHz, 18kHz, 19kHz, 20kHz, 21kHz, 22kHz, 23kHz, 24kHz or 25kHz, but is not limited to the recited values, and other non-recited values within the numerical range are equally applicable.

Preferably, the ultrasonic wave has an amplitude of 5 to 45 μm, and may be, for example, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm or 45 μm, but not limited to the recited values, and other values not recited in the numerical range are equally applicable.

Preferably, the power of the ultrasonic wave is 800-2000W, for example, 800W, 900W, 1000W, 1100W, 1200W, 1300W, 1400W, 1500W, 1600W, 1700W, 1800W, 1900W or 2000W, but not limited to the recited values, and other non-recited values in the range of values are equally applicable.

Preferably, the time of the soaking treatment of the back plate is 5-15min, for example, may be 5min, 6min, 8min, 10min, 12min, 14min or 15min, but is not limited to the recited values, and other non-recited values in the numerical range are equally applicable.

Preferably, the time of the immersion treatment of the tungsten silicon target is 15-25min, for example, 15min, 16min, 17min, 18min, 19min, 20min, 21min, 22min, 23min, 24min or 25min, but not limited to the recited values, and other non-recited values in the numerical range are equally applicable.

In the invention, by preferably controlling the frequency, amplitude, power and time of the ultrasonic wave in the immersion treatment, the solder can be better spread and filled in the welding gap, thereby improving the welding strength.

Preferably, the pressure of the pressurizing treatment in the step (3) is 5-10MPa, for example, 5MPa, 5.5MPa, 6MPa, 6.5MPa, 7MPa, 7.5MPa, 8MPa, 8.5MPa, 9MPa, 9.5MPa or 10MPa, but not limited to the values listed, and other values not listed in the numerical range are equally applicable.

Preferably, the pressurizing treatment includes placing a compact on an upper surface of the target assembly.

Preferably, the ratio of the contact area of the pressing block and the target assembly to the upper surface area is more than or equal to 60%, for example, 60%, 65%, 70%, 75%, 80%, 85% or 90%, but is not limited to the recited values, and other non-recited values in the numerical range are equally applicable.

According to the invention, the densification of welding can be promoted, the welding defects are reduced, the stress concentration in the welding process is reduced, and the excessive deformation of the target assembly is avoided by preferably controlling the pressure of the pressurizing treatment and the proportion of the contact area of the pressing block and the target assembly to the upper surface area.

Preferably, the cooling rate in step (3) is less than or equal to 10 ℃ per minute, and may be, for example, 10 ℃, 9 ℃, 8 ℃, 7 ℃,6 ℃ or 5 ℃ per minute, but is not limited to the recited values, and other values not recited in the range of values are equally applicable.

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

(1) Respectively machining a copper-chromium alloy backboard and a tungsten-silicon target, wherein an assembly groove and a welding groove are sequentially and concentrically arranged on the welding surface of the backboard from top to bottom, the depth of the welding groove is 2-4mm, the diameter of the welding groove is smaller than that of the target and the difference is 4-6mm, the surface roughness Ra of the backboard after machining is 4-8 mu m, and the surface roughness Ra of the tungsten-silicon target is 7-12 mu m, so that a pretreated backboard and a pretreated target are obtained;

(2) Filling the solder tank of the pretreated backboard obtained in the step (1) with indium solder, coating the welding surface of the pretreated target with indium solder, heating the backboard and the target at a temperature rising rate of less than or equal to 10 ℃ per minute to a final point temperature of 190-230 ℃ to melt the solder, and respectively carrying out infiltration treatment on the welding surface of the backboard and the target, wherein the infiltration treatment is carried out under the condition of ultrasonic waves, the frequency of the ultrasonic waves is 15-25kHz, the amplitude of the ultrasonic waves is 5-45 mu m, the power of the ultrasonic waves is 800-2000W, the infiltration treatment time of the backboard is 5-15min, and the infiltration treatment time of the tungsten-silicon target is 15-25min, so that the infiltrated backboard and target are obtained;

(3) Assembling the infiltrated backboard obtained in the step (2) and the target material to obtain a target material assembly, carrying out pressurization treatment on the target material assembly, wherein the pressure of the pressurization treatment is 5-10MPa, and then cooling at the speed of less than or equal to 10 ℃ per minute to obtain the welded target material assembly.

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

According to the preparation method provided by the invention, the butt joint of the target and the backboard is ensured by arranging the assembly groove and the welding groove, enough welding flux can be filled in the welding groove, and the problem of insufficient welding flux is avoided, so that the welding surface is fully soaked, and the tiny gaps in the welding process are eliminated by pressurizing, so that the welding surface is fully filled with the welding flux, the welding strength is further enhanced, and meanwhile, the excessive deformation of the target component is prevented. Under the preferred condition, the preparation method provided by the invention can enable the welding bonding strength of the target assembly to be more than 20MPa and the deformation to be less than 0.1 mm.

Drawings

Fig. 1 is a schematic structural diagram of a target assembly according to embodiment 1 of the present invention;

1-target material, 2-backboard, 3-assembly groove and 4-solder groove.

Detailed Description

The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

Example 1

The embodiment provides a welding method of a large-size tungsten silicon alloy target, which comprises the following steps:

(1) Respectively machining a copper-chromium alloy backboard and a tungsten-silicon target (with the diameter of 420mm and the thickness of 13 mm), wherein the surface roughness Ra of the backboard after machining is 6 mu m, and the surface roughness Ra of the tungsten-silicon target is 10 mu m, so as to obtain a pretreated backboard and a pretreated target;

As shown in fig. 1, the machining further comprises concentrically arranging an assembly groove 3 and a solder groove 4 on the welding surface of the back plate 2 from top to bottom, wherein the depth of the solder groove 4 is 3mm, and the diameter of the solder groove 4 is smaller than the diameter of the target 1 and the difference is 5mm;

(2) Filling the solder tank of the pretreated backboard obtained in the step (1) with indium solder, coating the welding surface of the pretreated target with indium solder, heating the backboard and the target at a temperature rising rate of 10 ℃ per minute to a final point temperature of 210 ℃ to melt the solder, and then respectively carrying out infiltration treatment on the welding surface of the backboard and the target, wherein the infiltration treatment is carried out under the condition of ultrasonic waves, the frequency of the ultrasonic waves is 20kHz, the amplitude of the ultrasonic waves is 25 mu m, the power of the ultrasonic waves is 1400W, the time of the infiltration treatment of the backboard is 10min, and the time of the infiltration treatment of the tungsten silicon target is 20min, so that the infiltrated backboard and target are obtained;

(3) Assembling the infiltrated backboard obtained in the step (2) and the target to obtain a target assembly, placing a pressing block on the upper surface of the target assembly for pressurizing treatment, wherein the contact area of the pressing block and the target assembly accounts for 60% of the area of the upper surface, the pressurizing treatment pressure is 8MPa, and then cooling at the speed of 10 ℃ per minute to obtain the welded target assembly.

Example 2

The embodiment provides a welding method of a large-size tungsten silicon alloy target, which comprises the following steps:

(1) Respectively machining a copper-chromium alloy backboard and a tungsten-silicon target (with the diameter of 420mm and the thickness of 13 mm), wherein an assembly groove and a welding groove are concentrically arranged on the welding surface of the backboard from top to bottom in sequence, the depth of the welding groove is 2mm, the diameter of the welding groove is smaller than the diameter of the target and the difference is 4mm, the surface roughness Ra of the backboard after machining is 8 mu m, and the surface roughness Ra of the tungsten-silicon target is 7 mu m, so that a pretreated backboard and a pretreated target are obtained;

(2) Filling the solder tank of the pretreated backboard obtained in the step (1) with indium solder, coating the welding surface of the pretreated target with indium solder, heating the backboard and the target at a heating rate of 8 ℃ per minute to a final point temperature of 230 ℃ to melt the solder, and then respectively carrying out infiltration treatment on the welding surfaces of the backboard and the target, wherein the infiltration treatment is carried out under the condition of ultrasonic waves, the frequency of the ultrasonic waves is 15kHz, the amplitude of the ultrasonic waves is 45 mu m, the power of the ultrasonic waves is 800W, the time of the infiltration treatment of the backboard is 15min, and the time of the infiltration treatment of the tungsten silicon target is 15min, so that the infiltrated backboard and target are obtained;

(3) Assembling the infiltrated backboard obtained in the step (2) and the target to obtain a target assembly, placing a pressing block on the upper surface of the target assembly for pressurizing treatment, wherein the contact area of the pressing block and the target assembly accounts for 65% of the area of the upper surface, the pressurizing treatment pressure is 5MPa, and then cooling at the speed of 8 ℃ per minute to obtain the welded target assembly.

Example 3

The embodiment provides a welding method of a large-size tungsten silicon alloy target, which comprises the following steps:

(1) Respectively machining a copper-chromium alloy backboard and a tungsten-silicon target (with the diameter of 420mm and the thickness of 13 mm), wherein an assembly groove and a welding groove are concentrically arranged on the welding surface of the backboard from top to bottom in sequence, the depth of the welding groove is 4mm, the diameter of the welding groove is smaller than the diameter of the target and the difference is 6mm, the surface roughness Ra of the backboard after machining is 4 mu m, and the surface roughness Ra of the tungsten-silicon target is 12 mu m, so as to obtain a pretreated backboard and a pretreated target;

(2) Filling the solder tank of the pretreated backboard obtained in the step (1) with indium solder, coating the welding surface of the pretreated target with indium solder, heating the backboard and the target at a temperature rising rate of 6 ℃ per minute to a final point temperature of 190 ℃ to melt the solder, and then respectively carrying out infiltration treatment on the welding surface of the backboard and the target, wherein the infiltration treatment is carried out under the condition of ultrasonic waves, the frequency of the ultrasonic waves is 25kHz, the amplitude of the ultrasonic waves is 5 mu m, the power of the ultrasonic waves is 2000W, the time of the infiltration treatment of the backboard is 5min, the time of the infiltration treatment of the tungsten silicon target is 25min, and the infiltrated backboard and target are obtained;

(3) Assembling the infiltrated backboard obtained in the step (2) and the target to obtain a target assembly, placing a pressing block on the upper surface of the target assembly for pressurizing treatment, wherein the contact area of the pressing block and the target assembly accounts for 75% of the area of the upper surface, the pressurizing treatment pressure is 10MPa, and then cooling at the speed of 9 ℃ per minute to obtain the welded target assembly.

Example 4

This example provides a method for welding a large-sized tungsten silicon alloy target, which differs from example 1 only in that the surface roughness Ra of the tungsten silicon target after machining is 3 μm.

Example 5

This example provides a method for welding a large-sized tungsten silicon alloy target, which differs from example 1 only in that the surface roughness Ra of the tungsten silicon target after machining is 20 μm.

Example 6

This example provides a method of welding a large-sized tungsten silicon alloy target, which differs from example 1 only in that the difference between the diameter of the solder pot and the diameter of the target is 1mm.

Example 7

This example provides a method of welding a large-sized tungsten silicon alloy target, which differs from example 1 only in that the difference between the diameter of the solder pot and the diameter of the target is 10mm.

Example 8

This example provides a method for welding a large-sized tungsten silicon alloy target, which differs from example 1 only in that the power of the ultrasonic wave is 500W.

Example 9

This example provides a method for welding a large-sized tungsten silicon alloy target, which differs from example 1 only in that the frequency of the ultrasonic wave is 10kHz.

Example 10

This example provides a method for welding a large-sized tungsten-silicon alloy target, which differs from example 1 only in that the pressure of the pressurizing treatment is 2MPa.

Example 11

This example provides a method for welding a large-sized tungsten-silicon alloy target, which differs from example 1 only in that the pressure of the pressurizing treatment is 15MPa.

Example 12

The embodiment provides a welding method of a large-size tungsten silicon alloy target, and the manufacturing method is different from embodiment 1 only in that the contact area of a pressing block and a target assembly occupies 40% of the upper surface area.

Comparative example 1

This comparative example provides a method of soldering a large-sized tungsten silicon alloy target, which differs from that of example 1 only in that no solder bath is provided and only solder is applied to the soldering face of the back plate.

The target assemblies of examples 1-12 and comparative example 1 were tested for weld bond strength using tensile testing and the results are shown in table 1.

The deformation amounts of the target assemblies in examples 1 to 12 and comparative example 1 were measured using a three-coordinate measuring machine, and the results are shown in table 1.

TABLE 1

	Welding bond strength/MPa	Deflection/mm
			Example 1	23	0.05
Example 2	22	0.07
			Example 3	20	0.08
Example 4	18	0.05
			Example 5	15	0.05
Example 6	17	0.07
			Example 7	12	0.05
Example 8	11	0.05
			Example 9	10	0.05
Example 10	13	0.03
			Example 11	23	0.24
Example 12	20	0.18
			Comparative example 1	8	0.04

From the data in Table 1, the following points can be seen:

(1) From the data of examples 1-12, the preparation method provided by the invention can enable the welding bonding strength of the target assembly to be more than 20MPa and the deformation to be less than 0.1mm under a better condition.

(2) As can be seen from a combination of the data of example 1 and examples 4-5, the present invention can facilitate sufficiently uniform wetting of the solder on the soldering surface and improve the soldering strength by preferably controlling the surface roughness of the backing plate and the target.

(3) As can be seen from the data of comparative examples 1, 6-7 and 1, the invention can effectively prevent the solder from overflowing during the welding process, ensure the solder to be uniformly distributed during the welding process, and ensure the proper contact area between the solder and the target and the backing plate and the welding strength by arranging the solder groove on the backing plate and preferably controlling the difference between the diameter of the solder groove and the diameter of the target.

(4) As can be seen from a comparison of the data of examples 1 and 8-9, the present invention can contribute to sufficiently uniform wetting of the solder on the soldering surface and increase the soldering strength by preferably controlling the frequency and power of the ultrasonic wave.

(5) As can be seen from the data of comparative examples 1 and 10 to 12, the present invention can improve the welding strength and avoid excessive deformation of the target by preferably controlling the pressure of the pressurizing treatment and the ratio of the contact area of the press block and the target assembly to the upper surface area.

In summary, the welding method provided by the invention can effectively improve the welding bonding strength of the target and the backboard, avoid the target assembly from being unwelded and cracked, and reduce the deformation caused by welding.

The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.

Claims (10)

1. The welding method of the large-size tungsten-silicon alloy target is characterized by comprising the following steps of:

(1) Respectively machining a backboard and a tungsten silicon target, wherein an assembly groove and a welding groove are sequentially and concentrically arranged on a welding surface of the backboard from top to bottom, and the diameter of the welding groove is smaller than that of the target, so that a pretreated backboard and a pretreated target are obtained;

(2) Filling the solder in the solder tank of the pretreated backboard obtained in the step (1), coating the solder on the welding surface of the pretreated target material, heating the backboard and the target material to melt the solder, and respectively carrying out infiltration treatment on the welding surfaces of the backboard and the target material to obtain the infiltrated backboard and the target material;

(3) Assembling the infiltrated backboard obtained in the step (2) with the target to obtain a target assembly, performing pressurization treatment on the target assembly, and then cooling to obtain the welded target assembly.

2. The method of soldering according to claim 1, wherein the back plate of step (1) comprises a copper chromium alloy back plate.

3. The welding method according to claim 1 or 2, wherein the diameter of the tungsten silicon target material in the step (1) is more than or equal to 420mm;

Preferably, the thickness of the tungsten silicon target is less than or equal to 13mm.

4. A welding method according to any one of claims 1 to 3, characterized in that after said machining in step (1), the surface roughness Ra of the backing plate is 4-8 μm;

preferably, after the machining, the surface roughness Ra of the tungsten silicon target is 7-12 mu m.

5. The welding method according to any one of claims 1 to 4, wherein the difference between the diameter of the solder pot and the diameter of the target in step (1) is 4 to 6mm;

Preferably, the depth of the solder bath is 2-4mm.

6. The soldering method according to any one of claims 1 to 5, wherein the solder in step (2) comprises indium solder;

Preferably, the heating rate is less than or equal to 10 ℃ per minute;

Preferably, the end temperature of the heating is 190-230 ℃.

7. The welding method according to any one of claims 1 to 6, wherein the infiltration treatment of step (2) is performed under ultrasonic conditions;

preferably, the frequency of the ultrasonic wave is 15-25kHz;

preferably, the amplitude of the ultrasonic wave is 5-45 μm;

Preferably, the power of the ultrasonic wave is 800-2000W;

preferably, the time of the soaking treatment of the backboard is 5-15min;

Preferably, the time of the infiltration treatment of the tungsten silicon target is 15-25min.

8. The production method according to any one of claims 1 to 7, wherein the pressure of the pressure treatment in step (3) is 5 to 10MPa;

preferably, the pressurizing process includes placing a compact on an upper surface of the target assembly;

preferably, the contact area of the pressing block and the target assembly occupies more than or equal to 60 percent of the upper surface area.

9. The method according to any one of claims 1 to 8, wherein the cooling rate in step (3) is 10 ℃ per minute or less.

10. The preparation method according to any one of claims 1 to 9, characterized in that the preparation method comprises the steps of:

(1) Respectively machining a copper-chromium alloy backboard and a tungsten-silicon target, wherein an assembly groove and a welding groove are sequentially and concentrically arranged on the welding surface of the backboard from top to bottom, the depth of the welding groove is 2-4mm, the diameter of the welding groove is smaller than that of the target and the difference is 4-6mm, the surface roughness Ra of the backboard after machining is 4-8 mu m, and the surface roughness Ra of the tungsten-silicon target is 7-12 mu m, so that a pretreated backboard and a pretreated target are obtained;

(2) Filling the solder tank of the pretreated backboard obtained in the step (1) with indium solder, coating the welding surface of the pretreated target with indium solder, heating the backboard and the target at a temperature rising rate of less than or equal to 10 ℃ per minute to a final point temperature of 190-230 ℃ to melt the solder, and respectively carrying out infiltration treatment on the welding surface of the backboard and the target, wherein the infiltration treatment is carried out under the condition of ultrasonic waves, the frequency of the ultrasonic waves is 15-25kHz, the amplitude of the ultrasonic waves is 5-45 mu m, the power of the ultrasonic waves is 800-2000W, the infiltration treatment time of the backboard is 5-15min, and the infiltration treatment time of the tungsten-silicon target is 15-25min, so that the infiltrated backboard and target are obtained;

(3) Assembling the infiltrated backboard obtained in the step (2) and the target material to obtain a target material assembly, carrying out pressurization treatment on the target material assembly, wherein the pressure of the pressurization treatment is 5-10MPa, and then cooling at the speed of less than or equal to 10 ℃ per minute to obtain the welded target material assembly.