TWI619561B - Rotating target - Google Patents

Abstract

The present invention relates to a rotating target comprising a target body, a backing tube and a joint member, the joint member being disposed between the target body and the backing tube, and the joint member comprising a compressible member The structure is electrically conductive and thermally conductive, and the compressible structure is a compressible blanket or a compressible sheet. The use of the joint member to join the target body and the backing tube can not only simplify the process of rotating the target, but also improve the sputtering strength of the rotating target while maintaining the bonding strength between the target body and the backing tube. The degree of acceptance increases the sputtering efficiency.

Description

Rotating target

This creation relates to the field of sputtering technology, especially a rotating target.

Magnetron sputtering is to increase the liberation rate and sputtering efficiency by adding a magnetic control device to the sputtering system to change the movement of electrons in the plasma by the electromagnetic effect between the magnetic field and the electric field. purpose. When sputtering a flat target with magnetron sputtering, the sputtering behavior will focus on the surface area of the target with the strongest tangential magnetic field, forming a runway-type ablation, and even applying the planar target to the magnetron sputtering process. The rate is only about 35% to 50%.

In order to solve the problem of the application of the planar target to the magnetron sputtering process, in the prior art, when the magnetron sputtering process is performed, the rotary sputtering target is used instead. As described in Taiwan Patent No. I534283, since the rotating target can obtain a uniform ablated surface in the magnetron sputtering process, it can not only increase the target utilization rate to 70% to 80%, but also contribute to the extension. The life of the target, reducing manufacturing costs, increasing process throughput, and even improving the quality of the sputtered film.

However, the bonding technique of the target body of the rotating target and the backing tube is much more complicated than the bonding technique of the target body of the planar target and the planar back sheet. Most of the prior art uses a low melting point metal as a solder to fill the solder. Enter the gap between the target body of the rotating target and the backing tube to achieve the purpose of joining.

Since the hollow columnar target body is not easy to apply pressure during bonding, the bonding force between the target body and the backing tube is poor, and the target body and the backing are easily generated in a sputtering process at a certain temperature. The risk of tube detachment; and because the backing tube, solder and target body are composed of materials with different coefficients of thermal expansion, in the soldering or sputtering process, between the target body and the solder and between the solder and the solder The interface between the backing tubes will generate thermal stress with temperature change. When the target body is thinned by a sputtering time, the stress may be greater than the strength of the target body, and the target body may be generated. rupture.

In addition, when the solder solidifies, its volume may shrink to cause interfacial shrinkage stress. The heat and stress accumulated during sputtering often cause the bonding layer to be detached from the backing tube or the target body. If the area of the detachment is large to some extent, the amount of heat transferred from the target body to the backing tube during sputtering will be The rapid reduction leads to local overheating of the target body, which causes more uneven thermal stress, which eventually causes the target body to rupture during sputtering, interrupting the film deposition process.

In view of the above technical problems, the prior art proposes two different technical means to try to improve the problem of cracking of the target body.

One of the technical means is to apply a substance having a coefficient of thermal expansion between the solder and the target body to the solder and the target, as disclosed in Japanese Laid-Open Patent Publication No. Hei. No. Hei. 6-301156. The joint surface of the body forms an intermediate layer on the joint surface to reduce the stress caused by the temperature change through the intermediate layer. However, in this way, it is not only impossible to specifically overcome the risk of the target body of the rotating target being detached from the backing tube, and the use of such a method to reduce the stress more complicates the joining process, and increases the manufacturing cost of the rotating target.

Further, as disclosed in Taiwan Patent No. 555874, another technical means is to replace the solder with a compressive bonding material, and the bonding material is used to bond the target body and the backing tube. However, the use of a relatively loose material as a bonding material does not smoothly carry away the heat accumulated by the target body during sputtering, so that the sputtering target power tolerance of the rotating target is poor, and it is difficult to effectively extend the rotating target. Service life.

In view of the above technical deficiencies, one of the aims of the present invention is to simplify the process of rotating a target. Another purpose of this creation is to balance the joint force between the target body and the backing tube in the rotating target, and improve the power tolerance of the rotating target during sputtering, thereby prolonging the service life and lifting of the rotating target. The sputtering efficiency of the rotating target.

In order to achieve the foregoing object, the present invention provides a rotating target comprising a target body, a backing tube and a joint member, the joint member being disposed between the target body and the backing tube for The target body and the backing tube are tightly joined. Wherein, the joint member comprises a compressible structure and a conductive thermally conductive adhesive, and the compressible structure is a compressible blanket or a compressible sheet.

Preferably, the joint member is formed by a compressible structure in which the conductive paste is adsorbed. Accordingly, the composite joint member composed of the compressible structure and the conductive heat conductive adhesive can not only provide the functions of bonding, conduction, heat conduction, etc., but also has a slight deformation capability, thereby facilitating the elimination of the bonding process and the sputtering process. The stress generated in the film, thereby suppressing the cause of the fracture of the target body, and increasing the sputtering power tolerance of the target.

Preferably, the compressible structure of the joint member can be a structure having both electrical conductivity, thermal conductivity and compressibility, such as graphite blanket, graphite sheet, carbon blanket, carbon sheet, metal wire. Or a combination thereof.

Preferably, in one embodiment, the conductive and thermally conductive adhesive of the bonding member is composed of a thermosetting resin.

Preferably, in another embodiment, the conductive conductive paste of the bonding member comprises conductive particles and a thermosetting resin, and the conductive particles may be aluminum particles, gold particles, silver particles, copper particles, zinc particles, iron particles, The nickel particles or a combination thereof is not limited thereto; and the thermosetting resin may be a binder resin, and the material may be an epoxy resin, but is not limited thereto. Accordingly, after the compressible structure adsorbing the conductive paste is loaded into the gap between the backing tube and the target body, a simple heating step can be used to complete the bonding process of the entire rotating target, thereby simplifying the process of rotating the target. The purpose.

Preferably, the conductive particles in the conductive paste have a content of 10 to 60% by volume.

For example, the conductive paste can be, for example, a variety of commercially available products that are both electrically conductive and thermally conductive, such as AF30 or EC1660 sold by 3M or other Toshiba (GE) or Dow Chemical Company. product.

Preferably, the bonding member has a thermal conductivity greater than 20 W/m, and the bonding member has a resistivity of less than 5 x 10 ^-3 Ω ̇cm.

Preferably, the target body may be a hollow target body, and the target body may be made of a ceramic material, a metal material or a composite material, for example: aluminum zinc oxide, indium gallium oxide, boron zinc oxide , molybdenum, niobium or a combination thereof, but not limited to this.

Preferably, the backing tube can be made of a metal having high strength and high thermal conductivity, such as copper, a copper-containing alloy, an aluminum alloy-containing, titanium or stainless steel, but is not limited thereto.

According to the present invention, the use of a joint member having electrical conductivity, thermal conductivity and compressibility to join the target body and the backing tube can not only simplify the process of rotating the target but also ensure the target body and the back of the rotating target. The liner can be tightly joined (ie, maintain a certain bonding strength between the target body and the backing tube), while improving the sputtering power tolerance of the rotating target, thereby shortening the time required for the sputtering process and improving the rotating target Sputtering efficiency of the material.

The following is a description of several rotating targets as an example to illustrate the implementation of the present invention; those skilled in the art can easily understand the advantages and effects of the present invention through the contents of the present specification, and do not deviate from the spirit of the present creation. Various modifications and changes are made to implement or apply the content of this creation.

In this experiment, the target bodies of different materials were joined to the backing tube by using joint members of various materials, and the rotating targets of Examples 1 and 2 and Comparative Examples 1 to 6 were obtained. The specific preparation method of the rotating target of each of the examples and the comparative examples is as follows.

Example 1 and 2

First, prepare a backing tube with an inner diameter of 125 mm, an outer diameter of 133 mm and a length of 1500 mm. The materials of the backing tubes of the respective examples and comparative examples are shown in Table 1 below.

Next, a hollow target body having an inner diameter of 142 mm, an outer diameter of 154 mm, and a length of 700 mm is formed by a process of sintering, casting, or the like. The materials of the target bodies of the respective examples and comparative examples are shown in Table 1 below. Here, when the hollow target body of the rotating target of the first embodiment is produced, the indium tin oxide (ITO) is formed into a hollow target body by a process such as sintering and processing; When the hollow target body of the target is rotated, the hollow target body is formed by a process such as casting and processing of molybdenum (Mo).

Then, as shown in FIG. 1, the assembly aid A is selected, the backing tube 10 is first loaded on the assembly aid A, and the backing tube 10 and the graphite blanket impregnated with the conductive thermal adhesive are assembled to the hollow target body. In 20, the assembly containing the hollow target body 20, the joint member 30 containing the graphite blanket and the conductive paste, and the backing tube 10 is heated to 250 ° C to 450 ° C for 5 minutes, and then placed. The rotating target is obtained by gradually cooling at room temperature. The materials of the joint members of the respective examples are shown in Table 1 below.

More specifically, in Embodiment 1, the conductive thermally conductive adhesive is composed of a thermosetting resin and does not contain a metal powder; and in Embodiment 2, the conductive thermally conductive adhesive comprises a metal powder and a thermosetting resin, and the conductive heat conduction The glue contains 10 vol% to 60 vol% of aluminum or copper metal powder.

Comparative example 1 and 2

First, prepare a backing tube with an inner diameter of 125 mm, an outer diameter of 133 mm and a length of 1500 mm. The materials of the backing tube of each comparative example are shown in Table 1 below.

Next, a hollow target body having an inner diameter of 142 mm, an outer diameter of 154 mm, and a length of 700 mm is formed by a process of sintering, casting, or the like. The materials of the target bodies of the respective comparative examples are shown in Table 1 below. When the hollow target body of the rotating target of Comparative Example 1 was produced, the aluminum zinc oxide (AZO) was formed into a hollow target body by a process such as sintering and processing; when the rotary target of Comparative Example 2 was produced In the case of a hollow target body, the hollow target body is formed by a process such as casting and processing of niobium (Nb).

Finally, the hollow target body is inserted into the backing tube and placed in an environment of 170 ° C, and the molten indium solder is introduced into the gap between the hollow target body and the backing tube to contain the hollow shape. The components of the target body, the indium bonding material, and the backing tube were gradually cooled at room temperature, and the rotating targets of Comparative Examples 1 and 2 were obtained.

Comparative example 3 and 4

First, prepare a backing tube with an inner diameter of 125 mm, an outer diameter of 133 mm and a length of 1500 mm. The materials of the backing tube of each comparative example are shown in Table 1 below.

Next, a hollow target body having an inner diameter of 142 mm, an outer diameter of 154 mm, and a length of 700 mm is formed by a process of sintering, casting, or the like. The materials of the target bodies of the respective comparative examples are shown in Table 1 below. When the hollow target body of the rotating target of Comparative Example 3 was produced, the hollow target body was formed by a process such as casting and processing, and a hollow target of the rotating target of Comparative Example 4 was produced. In the case of the material, the aluminum-zinc oxide is formed into a hollow target body by a process such as sintering and processing.

Finally, the hollow target body is inserted into the backing tube, and an electrically and thermally conductive thermosetting resin (referred to as conductive heat conductive glue in Table 1 below) containing 10 vol% to 60 vol% of aluminum metal powder is introduced into the hollow target. The gap between the body and the backing tube is heated to 250 ° C to 450 ° C for 5 minutes, and then placed at room temperature, and the assembly containing the hollow target body, the conductive paste and the backing tube is heated. The rotating target of Comparative Examples 3 and 4 was obtained by gradually cooling.

In Comparative Examples 3 and 4, the electroconductive thermally conductive adhesive for forming the joint member was composed of an electrically and thermally conductive thermosetting resin containing 10 vol% to 60 vol% of the aluminum metal powder.

Comparative example 5 and 6

First, prepare a backing tube with an inner diameter of 125 mm, an outer diameter of 133 mm and a length of 1500 mm. The materials of the backing tubes of the respective examples and comparative examples are shown in Table 1 below.

Next, a hollow target body having an inner diameter of 142 mm, an outer diameter of 154 mm, and a length of 700 mm is formed by a process of sintering, casting, or the like. The materials of the target bodies of the respective examples and comparative examples are shown in Table 1 below. Here, when the hollow target body of the rotating target of Comparative Example 5 is produced, the in-line hollow target body is formed by sintering, processing, or the like; and the rotating target of Comparative Example 6 is produced. In the case of a hollow target body, the above-described hollow target body is formed by a process such as casting and processing of molybdenum.

Then, as shown in FIG. 1, the assembly aid A is selected, the backing tube 10 is first loaded on the assembly aid A, and the backing tube 10 and the joint 30 are assembled into the hollow target body 20, that is, The rotating targets of Comparative Examples 5 and 6 were obtained. The materials of the joint members of the respective examples and comparative examples are shown in Table 1 below. Table 1: Materials of the target body, the backing tube and the joint in the rotating target of Examples 1 and 2, and the shearing force of the rotating targets of Examples 1 and 2 and Comparative Examples 1 to 6 Tensile strength and its maximum withstand power.  <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> sample number</td><td> target body</td><td> backing Tube </td><td> joint piece </td><td> shear tensile strength (kg/cm²) </td><td> maximum withstand power (kW/m ²) </td></tr><tr><td> Example 1 </td><td> ITO </td><td> Ti </td><td> Graphite Blanket and conductive thermal paste</td><td> 21 </td><td> 20.2 </td></tr><tr><td> Example 2 </td><td> Mo </td> <td> 304 stainless steel</td><td> graphite blanket and conductive thermal paste</td><td> 21 </td><td> 21.7 </td></tr><tr><td> Comparative example 1 </td><td> AZO </td><td> 304 stainless steel</td><td> Indium solder</td><td> -- </td><td> 12.2 </td></ Tr><tr><td> Comparative Example 2 </td><td> Nb </td><td> Ti </td><td> Indium Solder</td><td> -- </td>< Td> 13.6 </td></tr><tr><td> Comparative Example 3 </td><td> Nb </td><td> 304 Stainless Steel </td><td> Conductive Thermal Conductive Adhesive</td ><td> 26 </td><td> 10.9 </td></tr><tr><td> Comparative Example 4 </td><td> AZO </td><td> Ti </td> <td> Conductive and Thermally Conductive Adhesive</td><td> 25 </td><td> 9.1 </td></tr><tr><td> Comparative Example 5 </td><td> ITO </td ><td> 304 Rust steel</td><td> graphite blanket</td><td> -- </td><td> 9.7 </td></tr><tr><td> Comparative Example 6 </td>< Td> Mo </td><td> Ti </td><td> graphite blanket</td><td> -- </td><td> 11.0 </td></tr></TBODY>< /TABLE>

Through the above preparation methods, the rotary target obtained by each of the examples and the comparative examples has a structure as shown in FIG. The rotating target has a backing tube 10, a hollow target body 20 and a joint member 30. The joint member 30 is disposed between the backing tube 10 and the hollow target body 20 to engage the back. The liner 10 and the hollow target body 20. The inner diameter D2 of the hollow target body 20 is greater than the inner diameter D1 of the backing tube 10 by about 9 mm, and the gap between the hollow target body 20 and the backing tube 10 is for accommodating the joint. Item 30.

Test case 1 : joint strength

In this test example, the rotating targets of the foregoing Examples 1 and 2 and Comparative Examples 3 and 4 were selected as test objects, and each rotating target was cut into test pieces for shear test to evaluate each rotation. The joint strength of the target. The geometric profile of each test piece is shown in Figure 3.

Each test piece has a total length of 166 mm and a width of 10 mm. Among them, the hollow target body and the backing tube have a length of 83 mm and a thickness of 3 mm, and the length of the joint member is 20 mm and the thickness is 4.5 mm.

Next, as shown in FIG. 3, when the test is performed by the universal testing machine, the end of the test piece is clamped by the jig (that is, the end of the backing tube 10 on the engaging member 30 is one end of the test piece, and is located on the engaging piece 30. The other end of the target body 20 is the other end of the test piece), one end of which is fixed, and the other end is applied with a tensile force F tensile test piece at a rate of 50 mm/min, and the average shear stress at the time of failure of the test piece is recorded. The results are shown in Table 1 above.

As shown in Table 1, whether it is the ceramic rotating target of the first embodiment or the metal rotating target of the second embodiment, the bonding strength of the rotating target is obtained by using the graphite blanket and the conductive thermal conductive adhesive as the material of the joint member. The joint strengths of the rotating targets as in Comparative Examples 3 and 4 were attained. The experimental results show that the graphite blanket and the conductive thermal adhesive can be used as the material of the joint, and the target body and the backing tube can be effectively joined to obtain a rotating target with good jointability.

Test case 2 : Maximum withstand power

In this test example, the rotating targets of the foregoing Examples 1 and 2 and Comparative Examples 1 to 6 were selected as test objects, and each of the rotating targets was placed in a sputtering chamber, which included a DC power supply and a grounding. A shield, a gas inlet, a vacuum pump, and a base for the substrate to be placed. In the sputtering process, the rotating target is connected to the power cathode, and a substrate is placed in the sputtering chamber, and then argon gas with a flow rate of 20 sccm is applied to the DC power of 100 W to 1500 W, and the sputtering chamber is used. The sputtering process is maintained at a vacuum of 5 mtorr.

Then, gradually increase the sputtering power within the range of the DC power, and observe whether the rotating target has a welding failure of the target body and the backing tube at a specific sputtering power, so that the target body cannot follow the backing tube. Rotating together or causing the target body to rupture, etc., when the foregoing conditions are observed, the DC power applied at that time is recorded, and the DC power is relative to the area of the target body, which is the maximum withstand power that the rotating target can withstand. . The results are shown in Table 1 above.

As shown in Table 1 above, whether the ceramic rotating target of the first embodiment or the metal rotating target of the second embodiment uses a graphite blanket and a conductive thermal conductive adhesive as the material of the bonding member, the rotating targets of the embodiments 1 and 2 are splashed. The maximum withstand power at the time of plating was greater than the maximum withstand power of the rotating targets of Comparative Examples 1 to 6 at the time of sputtering, and the sputtering power tolerance of the rotating targets of Examples 1 and 2 was significantly better than that of the comparative example. Sputter power tolerance of the rotating target of 1 to 6; in particular, the maximum withstand power of the rotating target of Examples 1 and 2 during sputtering is significantly greater than that of the rotating target of Comparative Examples 1 and 2 The maximum withstand power at the time.

In summary, the present invention uses a graphite blanket and a conductive thermal conductive adhesive as the material of the joint member. The joint of the hollow target body and the backing tube can not only take into account the joint strength of the two, but also greatly Improve the sputtering power tolerance of the rotating target, and at the same time help to improve the sputtering efficiency of the rotating target and extend the service life of the rotating target, which even makes the rotating target of the creation have superior development potential.

The above-described embodiments are merely illustrative of the present invention and are not intended to limit the scope of the claims claimed herein. The scope of the claims claimed herein is based on the scope of the patent application, and is not limited to the specific embodiments described above.

10 Backing tube 20 Hollow target body 30 Engagement A Assembly aid D1 Outer diameter D2 Inside diameter F Tension

1 is a schematic view showing the joining of a backing tube and a joint member to a target body by using an assembly aid when manufacturing the rotating targets of Examples 1 and 2 and Comparative Examples 5 and 6; FIG. 2 is a cross section of the rotating target. Schematic diagram of the structure; and Figure 3 is a schematic cross-sectional view of a test piece for performing a shear tensile test.

Claims (9)

A rotating target comprising a target body, a backing tube and a joint member disposed between the target body and the backing tube, and the joint member comprises a compressible structure and a conductive A thermally conductive adhesive, the compressible structure being a graphite blanket, a graphite sheet, a carbon blanket, a carbon sheet, or a combination thereof. A rotating target according to claim 1, wherein the engaging member is formed of a compressible structure to which the conductive thermally conductive adhesive is adsorbed. The rotating target of claim 1, wherein the bonding member has a thermal conductivity greater than 20 W/m. The rotating target of claim 1, wherein the joint has a resistivity of less than 5 x 10 ^-3 Ω ̇cm. The rotating target according to claim 1, wherein the conductive thermally conductive adhesive of the joining member is composed of a thermosetting resin. The rotating target according to claim 1, wherein the conductive conductive paste of the bonding member comprises a plurality of conductive particles and a thermosetting resin, and the conductive particles are contained in an amount of from 10% by volume to 60% by volume. The rotating target of claim 6, wherein the conductive particles are aluminum particles, gold particles, silver particles, copper particles, zinc particles, iron particles, nickel particles, or a combination thereof. A rotating target according to any one of claims 1 to 7, wherein the target system is made of a ceramic material, a metal material or a composite material. The rotating target of any one of claims 1 to 7, wherein the material of the backing tube is copper, a copper-containing alloy, an aluminum alloy-containing, titanium or stainless steel.