TWI412618B - Hollow columnar target and its components - Google Patents

Abstract

The invention relates to a hollow columnar target assembly, comprising a back-lining tube and a target material, wherein the target material is an external tube, and the back-lining tube is an inner tube. The inner tube is used for being engaged in the external tube. Under a state that the external tube is separated from the inner tube, the outer diameter of the inner tube is greater than the inner diameter of the external tube, and the difference between the outer diameter of the inner tube and the inner diameter of the external tube must be equal to that the inner diameter of the external tube multiplies by the yield strain of the target material and then multiplies by a coefficient N, wherein N is between 1 and 10. With the regulation of the material and parameters, the external tube can be closely engaged with the inner tube.

Description

Hollow cylindrical target and its components

The invention relates to a hollow columnar target, in particular to a hollow columnar target capable of tightly combining a target material and a backing tube and having a simple process.

In a magnetron sputtering process typically using a planar target, the sputtering behavior is concentrated on the surface area of the target with the strongest tangential magnetic field, forming a runway-type erosion trace, thereby reducing the target utilization rate. In general, the use of planar targets is only 35% to 50%.

A uniform etched surface can be obtained by using a rotating target, which improves the quality of the film in addition to increasing the usage rate to 70% to 80%. Increasing target life and utilization can reduce manufacturing costs, increase process throughput, reduce target purchase costs, and extend effective production time.

However, the bonding technique of the target material of the rotating target and the backing tube is much more complicated than the bonding technique of the general planar target and the backing plate. It is common practice to use a low melting point metal as a solder to fill the gap between the rotating target and the backing tube for bonding purposes. The use of a low-melting point metal as a solder has the advantage of less thermal stress. However, since the hollow columnar target is not easy to apply pressure during soldering, the bonding force is poor, and it is easy to occur in a deposition process at a certain temperature. The risk of the backing tube falling off. Other common ways include:

a. Spraying technology: the material of the target is plated on the outer tube wall of the backing tube by plasma or high pressure spraying to form a target. However, the sputtering method easily generates pores in the target, resulting in a decrease in the density of the target.

b. Casting technique: A tubular mold is placed outside the backing tube, and the molten target material is injected between the tubular mold and the backing tube to form a target. The limitation of the casting method is that it can only be used for the manufacture of targets with low melting point materials.

c. Electroplating: The backing tube is placed in a plating solution, and the target material is plated on the outer tube wall of the backing tube by electroplating to form a target. Although it has good adhesion, the deposition rate of the electroplating method is slow, and the thickness of the deposition is limited.

In U.S. Patent No. 5,435,965, the use of a grouting technique to inject a target material between a tubular mold and a backing tube, and then to increase the density of the target by a heat-averaged press; however, the hot press process is expensive. Increase the cost of target manufacturing.

In Japanese Patent Laid-Open No. Hei 11-71667, it is disclosed that the backing tube is directly inserted into the copper target material by the principle of thermal expansion and contraction, and the joint is completed by mechanical force; however, the bite amount is set at 0.01 mm to 0.5. Mm, does not consider the relationship between target size and bite. However, as shown by George M. Wityak's research paper (Performance Comparison of Silver Sleeved Rotary Targets with Planar Targets, George M. Wityak, Society of Vacuum Coaters, 49th Annual Technical Conference Proceedings (2005)), target size and occlusion If the amount is not properly designed, the target and the backing tube are not loosened, but the thermal conductivity and the poor electrical conductivity can be observed by the temperature change of the target in the sputtering process and the number of arc occurrences.

In addition, in U.S. Patent Application Publication No. 2004/0074770, it is disclosed that a target material is heated and expanded, and then placed over the backing tube, and then cooled to complete the joining. However, it does not take into account the various parameters between the target material and the backing tube, so the method still does not allow a tight bond between the backing tube and the target material.

The present inventors have in view of the fact that the bonding technology of the existing target material and the backing tube cannot make the target material and the backing tube tightly combined, and the other methods for manufacturing the target having the backing tube have their shortcomings, so Attempts and efforts have finally invented this hollow cylindrical target.

It is an object of the present invention to provide a hollow cylindrical target which is capable of tightly bonding a target material and a backing tube and having a simple process.

To achieve the above object, the present invention provides a hollow cylindrical target assembly comprising a backing tube and a target material, wherein the target material is an outer tube, the backing tube is an inner tube, and the inner tube is For engaging in the outer tube, in the state where the outer tube is separated from the inner tube, the outer diameter of the inner tube is larger than the inner diameter of the outer tube, and the difference between the outer diameter of the inner tube and the inner diameter of the outer tube is equal to the target The strain of the material is multiplied by the inner diameter of the outer tube and multiplied by a factor N, which is between 1 and 10.

Wherein the target material and the backing tube material are selected from the group consisting of metals, metal alloys, ceramic materials, nitrides, oxides, and combinations thereof.

Wherein, the inner tube wall of the outer tube has a groove.

Wherein, the outer tube wall of the inner tube has a groove.

Wherein, the inner tube wall of the outer tube and the outer tube wall of the inner tube have grooves.

Wherein, the hollow cylindrical target assembly further comprises a medium which is a conductive material disposed between the outer tube and the inner tube; or is disposed in a groove between the outer tube and the inner tube.

The invention further relates to a hollow cylindrical target comprising the hollow cylindrical target assembly described above, and the inner tube is joined within the outer tube.

The invention adjusts the outer diameter of the inner tube and the inner diameter of the outer tube by the different properties of the material of the target material and the backing tube, so that the difference is equal to the drop strain of the target material multiplied by the inner diameter of the outer tube and multiplied With a factor of N and controlling the value of N between 1 and 10, the outer tube and the inner tube can be tightly joined.

In order to reduce the manufacturing cost of the hollow cylindrical target and improve the joint strength between the target material and the backing tube, the present invention proposes a hollow cylindrical target and a manufacturing method thereof. In the present invention, the target material is the outer tube and the backing tube is the inner tube, and the difference between the outer diameter of the inner tube and the inner diameter of the outer tube is equal to the gradient strain of the target material multiplied by the inner diameter of the tube. Multiply by a factor N, the value of N is between 1 and 10; before the joint, the inner diameter of the outer tube is slightly smaller than the outer diameter of the inner tube; when the joint is applied, the appropriate temperature difference is applied to the inner and outer tubes to make the outer tube temperature Higher than the inner tube, the inner diameter of the outer tube is larger than the outer diameter of the inner tube by the principle of thermal expansion and contraction. Under this temperature difference, the inner tube is inserted into the outer tube for jointing, and the inner and outer tubes are joined after the original temperature is restored. .

Please refer to the first figure. R and r are the initial inner diameter of the outer tube (10) and the initial outer diameter of the inner tube (20), respectively, and r>R; the inner and outer tubes (10, 20) are given a temperature difference. According to the formula of thermal expansion and contraction, R' is approximately equal to R × (1 + K _a T _a ), and r' is approximately equal to r × (1 + K _b T _b ), where R', r' are thermal expansion or coefficient of thermal expansion of the outer tube (10) and the inner diameter of the inner tube (20) after the shrink outside diameter, K _a and K _b are the outer tube (10) and the inner tube (20) of, T _a and T _b are respectively The difference in temperature between the outer tube (10) and the temperature difference in the inner tube (20). When the temperature of the outer tube (10) is sufficiently higher than the inner tube (20) to make R'>r', the bonding process can be performed.

The difference (rR) between the initial outer tube inner diameter R and the inner tube outer diameter r is called the bite amount, that is, the difference between the outer diameter of the inner tube and the inner diameter of the outer tube, the outer diameter of the inner tube and the outer tube The difference in the range of the inner diameter (the amount of nip) affects the strength of the joint and the mechanical stress experienced by the inner and outer tubes.

The design of the bite amount is closely related to the mechanical properties of the material and the size of the target. In the preferred case, the strain should be set after the material is subjected to the strain, if the strain of the target material is less than the strain of the material. The problem of heat conduction and poor conductivity due to insufficient tightness of the joint may cause the target temperature to rise and multiple abnormal discharges during the process; however, if the strain is greater than the strain of the material, the machine will be too high. Stress causes deformation or damage of the target and cannot be used. Therefore, after experimental research, the strain should be set above the deflection strain of the target material, and there will be better joint effect below 10 times of the strain. The bite amount is equal to the drop strain of the target material. The path is multiplied by a factor N, which is between 1 and 10.

In addition, in the present invention, the plastic deformation caused by the stress between the outer tube and the inner tube allows the inner and outer tubes to be tightly joined, so that solder is not required as a medium, but the medium can be added between the inner and outer tubes before the joint is performed. The conduction between electricity and heat between tubes or the ability to increase adhesion.

Please refer to the second and third figures. In order to achieve the convenience of the process and the purpose of saving solder, the wall (11) or the tube wall (21) or the above may be outside the inner wall (11) or the inner tube (20). The recesses (12, 22) are provided in the recesses (12, 22), and the solder is filled in the recesses (12, 22). This step of filling the solder can be performed after the bonding, but also after the bonding.

Referring to the fourth figure, wherein the inner tube (20) is taken as an example, the groove formed may be a plurality of grooves (22) respectively formed at both end portions (23) of the inner tube (20).

Alternatively, it may be a single groove that surrounds both ends of the inner wall (21) of the inner tube (20) or a single groove that surrounds the inner tube wall (11) of the outer tube (10). Simple.

Referring again to the fifth figure, the groove formed may be a plurality of grooves (22') extending from one end (23) of the inner tube (20) to the other end (23) to fill more The solder is such that the inner tube and the outer tube are more closely joined. The manner in which the groove is penetrated is not limited to a straight line, and may also spirally penetrate from one end of the inner tube to the other end.

Example

Embodiment 1:

A tubular silver target having a length of 1000.0 mm and an inner diameter of 132.5 mm was provided and joined to a tubular stainless steel backing tube having a length of 1400.0 mm and an outer diameter of 133.0 mm. Since the thermal expansion coefficient of silver is about 19.5×10 ^-6 /K, after the silver target is heated from room temperature to 25 ° C to 500 ° C, the inner diameter of the silver target becomes 133.7 mm, and the stainless steel at room temperature of 25 ° C is maintained. The backing tube was inserted into the silver target, and the silver target was cooled to room temperature to complete the joining, and the difference between the outer diameter of the inner tube and the inner diameter of the outer tube (biting amount) was 0.5 mm. The tubular silver target after joining has a degree of deflection and a perpendicularity of less than 0.05 mm, and the concentricity may be less than 1.0 mm. The downward strain of silver is about 0.25%, and the amount of the bite setting is about 0.38% for the inner diameter of 132.5 mm, which is about 1.5 times the assumed strain (N=1.5).

Embodiment 2:

A tubular indium tin oxide target having a length of 850.0 mm and an inner diameter of 70.0 mm was provided, and joined to a tubular stainless steel backing tube having a length of 1000.0 mm and an outer diameter of 70.15 mm. Since the thermal expansion coefficient of indium tin oxide is about 7.5×10 ^-6 /K, the thermal expansion coefficient of the stainless steel tube is about 10.5×10 ^-6 /K, and the indium tin oxide target is heated from room temperature 25 ° C to 525 ° C, indium tin oxide. The inner diameter of the target is changed to 70.26 mm; after the stainless steel tube is frozen from room temperature to 25 ° C to -75 ° C, the inner diameter of the stainless steel tube is changed to 70.08 mm; at this time, the stainless steel backing tube is inserted into the indium tin oxide target to be indium tin oxide. The target and the stainless steel tube were brought back to room temperature to complete the joint, and the bite amount was 0.15 mm. The tubular indium tin oxide target after bonding has a degree of deflection and a perpendicularity of less than 0.05 mm, and the concentricity may be less than 1.0 mm. The indium tin oxide has a drop strain of about 0.21%, and the bite amount is set to be about 0.21% for the inner diameter of 70.0 mm, which is about 1 times the drop strain (N = 1.0).

Embodiment 3:

A tubular aluminum target having a length of 1000.0 mm and an inner diameter of 100.0 mm was provided and joined to a tubular stainless steel backing tube having a length of 1400.0 mm and an outer diameter of 101.0 mm. Since the thermal expansion coefficient of aluminum is about 23.2×10 ^-6 /K, after the aluminum target is heated from room temperature to 25 ° C to 525 ° C, the inner diameter of the aluminum target becomes 101.2 mm, and the stainless steel at room temperature of 25 ° C is maintained. The backing tube was inserted into the aluminum target, and the joint was completed when the aluminum target was cooled to room temperature, and the difference (biting amount) between the outer diameter of the inner tube and the inner diameter of the outer tube was 1.0 mm. The tubular aluminum target after joining has a degree of deflection and a perpendicularity of less than 0.05 mm, and the concentricity may be less than 1.0 mm. The drop strain of aluminum is about 0.25%, and the amount of bite is set to about 1% for the inner diameter of 100.0 mm, which is about 4 times the strain (N=4).

Comparative example 1:

A tubular silver target having a length of 1000.0 mm and an inner diameter of 132.6 mm was provided and joined to a tubular stainless steel backing tube having a length of 1400.0 mm and an outer diameter of 132.8 mm. Since the thermal expansion coefficient of silver is 19.5×10 ^-6 /K, after the silver target is heated from room temperature to 25 ° C to 500 ° C, the inner diameter of the silver target becomes 133.8 mm, and the stainless steel back at room temperature of 25 ° C is maintained. The liner was inserted into the silver target, and the silver target was cooled to room temperature to complete the bonding, and the bite amount was 0.2 mm. The tubular silver target after joining has a degree of deflection and a perpendicularity of less than 0.05 mm, and the concentricity may be less than 1.0 mm. The amount of the bite setting was about 0.15% for the inner diameter of 132.6 mm, and about 0.6 times the drop strain (N=0.6).

The targets of the first, second, third and comparative examples were sputter-sputtered with the same sputtering parameters, and the targets of the first, second and third targets were adjusted from 1 kW to 5 kW. The temperature of the material is still below 50 °C; however, the target temperature of the target of Comparative Example 1 is greater than 150 ° C when the sputtering power is only 1 kW, indicating that the joint tightness is insufficient to cause poor thermal conductivity.

It can be seen from the above embodiment and the comparative example that the strain amount design in the first embodiment is about 1.5 times the strain of the target inner diameter, and the occlusion amount in the second embodiment is about the strain of the target inner diameter. For the 1.0 times of the strain, the amount of the bite design in Example 3 is about 4.0 times the strain of the target, and the control is about 0.6 times the strain; the bonded target in the example. The conductivity and heat dissipation were good, while the control example had a problem of severe heat dissipation. Therefore, the present invention solves the difficulty of fabricating a hollow cylindrical target by controlling the material of the inner tube and the outer tube and the amount of occlusion, that is, the basic principle of heat expansion and contraction, and the production of the tight joint by a simple process. Target materials and targets for backing tubes for industrial use.

(10). . . Outer tube

(11). . . Inner wall

(12). . . Groove

(20). . . Inner tube

(22)(22'). . . Groove

(twenty three). . . Ends

The first figure is a schematic end view of the outer tube and the inner tube of the present invention before being combined.

The second drawing is an end sectional view of the inner tube of the present invention.

The third drawing is an end sectional view of the outer tube of the present invention.

The fourth figure is a perspective view of an inner tube of the present invention.

The fifth drawing is a perspective view of another aspect of the inner tube of the present invention.

(10). . . Outer tube

(20). . . Inner tube

Claims (11)

A hollow cylindrical target assembly comprising a backing tube and a target material, wherein the target material is an outer tube, the backing tube is an inner tube, and the inner tube is for engaging in the outer tube In the state where the outer tube is separated from the inner tube, the outer diameter of the inner tube is larger than the inner diameter of the outer tube, and the difference between the outer diameter of the inner tube and the inner diameter of the outer tube is equal to the gradient strain of the target material. The inner diameter is multiplied by a factor N, which is between 1 and 10. The hollow columnar target assembly of claim 1, wherein the target material and the backing tube material are selected from the group consisting of metals, metal alloys, ceramic materials, nitrides, oxides, and combinations thereof. The group that makes up. The hollow cylindrical target assembly of claim 1, wherein the inner tube wall of the outer tube has a groove. The hollow cylindrical target assembly of claim 2, wherein the inner tube wall of the outer tube has a groove. The hollow cylindrical target assembly of claim 1, wherein the outer tube wall has a groove. The hollow cylindrical target assembly of claim 2, wherein the outer tube wall has a groove. The hollow cylindrical target assembly of claim 1, wherein the inner tube wall of the outer tube and the outer tube wall have grooves. The hollow cylindrical target assembly of claim 2, wherein the inner tube wall of the outer tube and the outer tube wall have grooves. The hollow cylindrical target assembly according to any one of claims 1 to 8, further comprising a medium which is a conductive material disposed between the outer tube and the inner tube. The hollow cylindrical target assembly according to any one of claims 3 to 8, further comprising a medium, the medium being a conductive material disposed in a groove between the outer tube and the inner tube . A hollow cylindrical target member comprising the hollow cylindrical target assembly according to any one of claims 1 to 10, and the inner tube is joined in the outer tube.