TW201803657A - Rotary sputtering target capable of improving sputtering power durability of the rotary sputtering target while keeping jointing strength between the target body and the back liner tube - Google Patents

Abstract

The present invention relates to a rotary sputtering target, which includes a target body, a back liner tube and a jointing member. The jointing member is arranged between the target body and the back liner tube, and the jointing member includes a compressible structure and electric-thermal conductive adhesive. The compressible structure is a compressible blanket or a compressible piece. The present invention can not only simplify the manufacturing process of the rotary sputtering target by using the jointing member to connect the target body and the back liner tube, but also improve sputtering power durability of the rotary sputtering target while keeping the jointing strength between the target body and the back liner tube, so as to increase sputtering efficiency.

Description

Rotating target

This creation is about the field of sputtering technology, especially a rotating target.

The magnetron sputtering method is to install a magnetron device in the sputtering system to change the movement of electrons in the plasma by the electromagnetic effect between the magnetic field and the electric field, so as to improve the ionization rate and sputtering efficiency. purpose. Traditionally, when magnetron sputtering is used to sputter a planar target, its sputtering behavior is concentrated on the surface area of the target with the strongest tangential magnetic field, forming a runway-type ablation, and even making the planar target used in the magnetron sputtering process. The rate is only about 35% to 50%.

In order to try to solve the problems existing when the planar target is applied to the magnetron sputtering process, in the prior art, when a magnetron sputtering process is performed, a rotary sputtering target is used instead. As described in Taiwan Invention Patent No. I534283, because the rotating target can obtain a uniform ablated surface during the magnetron sputtering process, it can not only increase the target utilization rate to 70% to 80%, but also help to extend Target life, reduce manufacturing costs, increase process yield, and even improve the quality of the sputtered film.

However, the joining technology between the target body of the rotating target and the backing tube is much more complicated than the joining technology of the target body of the flat target and the flat back plate. The existing technology mostly uses a low melting point metal as the solder and fills this solder. Into the gap between the target body of the rotating target and the backing tube to achieve the purpose of joining.

Since the hollow cylindrical target body is not easy to apply pressure during bonding, the bonding force between the target body and the backing pipe is poor, and the target body and the backing are liable to occur during the sputtering process at a certain temperature. Risk of tube detachment; and because the backing tube, solder, and target are all made of materials with different thermal expansion coefficients, during the welding or sputtering process, between the target and the solder, and between the solder and the target The interface between the backing pipes will generate thermal stress as the temperature changes. When the target body becomes thinner after a period of sputtering time, the stress may be greater than the strength of the target body, and the target body will be generated. rupture.

In addition, when the solder solidifies, its volume may shrink and interfacial shrinkage stress may occur. The heat and stress accumulated during sputtering often cause the bonding layer to detach from the backing pipe or the target body. If the area of this detachment is large to a certain extent, the amount of heat transferred from the target body to the backing pipe during sputtering will be The abrupt decrease leads to local overheating of the target body, which causes more uneven thermal stress, which eventually causes the target body to rupture during sputtering and interrupts the thin 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.

As disclosed in Japanese Patent Laid-Open No. 6-301156 and Japanese Patent Laid-Open No. 6-300734, one of the technical means is to apply a substance having a thermal expansion coefficient between the solder and the target body to the solder and the target. The joint surface of the body, an intermediate layer is formed on the joint surface to reduce the stress caused by the temperature change through the intermediate layer. However, using this method not only cannot specifically overcome the risk that the target body of the rotating target material is detached from the backing pipe, but also reduces the stress by using this method, which complicates the joining process and increases the manufacturing cost of the rotating target material.

As disclosed in Taiwan Invention Patent No. 555874, another technical method is to replace the solder with a compressive bonding material, and use this bonding material to join the target body and the backing tube. However, using a looser material as the bonding material cannot successfully remove the heat accumulated by the target body during sputtering, which results in poor resistance to the sputtering power of the rotating target material, and it is difficult to effectively extend the rotating target material. Service life.

In view of the above-mentioned technical defects, one of the purposes of this creation is to simplify the process of rotating the target. Another purpose of this creation is to take into account the bonding force between the target body and the backing tube in the rotating target material, and improve the power tolerance of the rotating target material during sputtering, thereby extending the service life of the rotating target material and improving Sputtering efficiency of rotating targets.

In order to achieve the foregoing object, the present invention provides a rotating target, the rotating target includes a target body, a backing pipe, and a joint member, the joint member is disposed between the target body and the backing pipe for Tightly join the target body and the backing tube. Wherein, the joint includes a compressible structure and a conductive thermal adhesive, and the compressible structure is a compressible blanket or a compressible sheet.

Preferably, the joint is formed by a compressible structure to which the conductive and thermally conductive glue is adsorbed. According to this, the composite joint composed of a compressible structure and a conductive thermal adhesive can not only provide functions such as bonding, electrical conduction, and thermal conductivity, but also has a slight deformation ability, which can help eliminate the bonding process and the sputtering process. The stress generated in the target can suppress the cause of the target body cracking and increase the sputtering power tolerance of the target.

Preferably, the compressible structure of the joint may be a structure having both electrical conductivity, thermal conductivity, and compressibility. The materials of the compressible structure are, for example, graphite blanket, graphite sheet, carbon blanket, carbon sheet, and metal wire. Or a combination.

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

Preferably, in another embodiment, the conductive thermal adhesive of the joint includes 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 are not limited thereto, and the thermosetting resin may be an adhesive resin, and the material thereof may be an epoxy resin, but is not limited thereto. According to this, after the compressible structure with the conductive and thermally conductive glue is filled into the gap between the backing tube and the target body, the entire process of joining the rotating target materials can be completed by a simple heating step, thereby simplifying the process of rotating the target material. Purpose.

Preferably, the content of the conductive particles in the conductive thermal adhesive is from 10% by volume to 60% by volume.

For example, its conductive and thermally conductive adhesive can be, for example, various commercially available products that have both electrical and thermal conductivity, such as AF30 or EC1660 products sold by 3M or other Toshiba (GE) or Dow Chemical companies. product.

Preferably, the thermal conductivity of the joint is greater than 20 W / m, and the electrical resistivity of the joint is 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, such as aluminum zinc oxide, indium gallium oxide, and boron zinc oxide. , Molybdenum, niobium, or a combination thereof, but not limited to this.

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

According to this creation, using a combination of conductive, thermal and compressive joints to join the target body and the backing tube can not only facilitate the process of rotating the target material, but also ensure the target body and back of the rotating target material. The liner can be tightly bonded (i.e., maintain a certain bonding strength between the target body and the backing tube), while improving the sputtering power tolerance of the rotating target, thereby reducing the time required for the sputtering process and improving the rotating target Sputtering efficiency of materials.

The following lists several types of rotating targets as examples to illustrate the implementation of this creation; those skilled in this art can easily understand the advantages and effects that this creation can achieve through the content of this manual, and without departing from the spirit of this creation Various modifications and changes are made to implement or apply the content of this creation.

In this experiment, various kinds of joints of different materials are used to join target bodies of different materials to the backing pipe, 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 material of each Example and a comparative example is as follows.

Examples 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 pipes of 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 after the raw materials of the target body are formed by processes such as sintering, melting, and processing. 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 material of Example 1 is produced, the aforementioned hollow target body is formed by indium tin oxide (ITO) through processes such as sintering and processing; when Example 2 is produced In the case of a hollow target body of a rotating target, molybdenum (Mo) is formed into the aforementioned hollow target body by processes such as melting casting and processing.

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

More specifically, in Example 1, the conductive thermal adhesive is composed of a thermosetting resin and does not contain a metal powder; in Example 2, the conductive thermal adhesive includes a metal powder and a thermosetting resin, and the thermal conductivity The glue contains 10 vol% to 60 vol% 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 material of the backing tube of each comparative example is 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 after the raw materials of the target body are produced through processes such as sintering, melting, and processing. The material of the target body of each comparative example is shown in Table 1 below. When the hollow target body of the rotating target material of Comparative Example 1 is produced, the aforementioned aluminum target body is formed by sintering and processing of aluminum zinc oxide (AZO); when the rotating target material of Comparative Example 2 is produced, In the case of a hollow target body, niobium (Nb) is formed into the aforementioned hollow target body by processes such as casting and processing.

Finally, insert the above-mentioned hollow target into the backing tube and place it in an environment of 170 ° C, and then introduce the molten indium solder into the gap between the hollow target and the backing tube to contain this hollow shape. The target body, the indium bonding material, and the components of the backing tube were gradually cooled at room temperature to obtain the rotating targets of Comparative Examples 1 and 2.

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 material of the backing tube of each comparative example is 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 after the raw materials of the target body are produced through processes such as sintering, melting, and processing. The material of the target body of each comparative example is shown in Table 1 below. When the hollow target body of the rotating target material of Comparative Example 3 is manufactured, the niobium target body is formed by niobium through processes such as casting and processing; when the hollow target of the rotating target material of Comparative Example 4 is produced In the case of a material body, the above-mentioned hollow target body is formed by a process such as sintering and processing of aluminum zinc oxide.

Finally, the above-mentioned hollow target body is inserted into the backing tube, and a conductive and thermally conductive thermosetting resin (referred to as a conductive thermal conductive adhesive in Table 1 below) containing an aluminum metal powder of 10 vol% to 60 vol% is introduced into the hollow target material. The gap between the body and the backing tube, and then heat the assembly containing the hollow target body, conductive thermal adhesive and backing tube to 250 ° C to 450 ° C for 5 minutes, and then place at room temperature After gradually cooling, the rotary targets of Comparative Examples 3 and 4 were obtained.

In Comparative Examples 3 and 4, the conductive and thermally conductive adhesive used to form the joint is composed of a conductive and thermally conductive thermosetting resin containing 10 vol% to 60 vol% of 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 pipes of 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 after the raw materials of the target body are produced through processes such as sintering, melting, and processing. 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 material of Comparative Example 5 is produced, the above-mentioned hollow target body is formed by indium tin oxide through processes such as sintering and processing; when the rotating target of Comparative Example 6 is produced In the case of a hollow target body, the hollow target body is formed by molybdenum through processes such as casting and processing.

Then, as shown in FIG. 1, the assembly auxiliary tool A is selected, and the backing pipe 10 is first loaded on the assembly auxiliary tool A, and then the backing pipe 10 and the joint member 30 are assembled into the hollow target body 20, that is, the manufacturing The rotary targets of Comparative Examples 5 and 6 were obtained. The materials of the joints of the respective examples and comparative examples are shown in Table 1 below. Table 1: Materials of target bodies, backing pipes, and joints among the rotary targets of Examples 1 and 2, and Comparative Examples 1 to 6, and shear forces of the rotary targets of Examples 1 and 2, and Comparative Examples 1 to 6 Tensile strength and its applicable maximum withstand power.

Through the aforementioned preparation method, the rotating target materials prepared in the respective examples and comparative examples have a structure as shown in FIG. 2. The rotating target has a backing tube 10, a hollow target body 20, and a joint 30, and the joint 30 is disposed between the backing tube 10 and the hollow target 20 to join the back The liner 10 and the hollow target body 20. The inner diameter D2 of the hollow target body 20 is larger 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 used to accommodate the aforementioned joint. Piece 30.

Test example 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 of the rotating targets was cut into a test piece to perform a shear test to evaluate each rotation. Target joint strength. The geometrical profile of each test piece is shown in Figure 3.

Each test piece was 166 mm long and 10 mm wide. Among them, the hollow target body and the backing tube each have a length of 83 mm and a thickness of 3 mm, and the length of the joint is 20 mm and the thickness is 4.5 mm.

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

As shown in Table 1, regardless of whether the ceramic rotating target material of Example 1 or the metal rotating target material of Example 2 uses graphite blanket and conductive thermal conductive adhesive as the material of the joining member, the joint strength of the prepared rotating target material is all It is possible to achieve the joint strength of the rotary targets as in Comparative Examples 3 and 4. The experimental results show that the use of graphite blankets and conductive thermal conductive adhesives as materials for the joints can still effectively join the target body and the backing tube, and obtain a rotating target with good bonding properties.

Test example 2 : Maximum withstand power

In this test example, the rotating targets of the foregoing Examples 1 and 2 and Comparative Examples 1 to 6 are selected as test objects, and each of the rotating targets is placed in a sputtering chamber, which contains a DC power supply and a ground. A shelter, a gas inlet, a vacuum pump, and a base on which the substrate can be placed. During sputtering, the rotating target is connected to the cathode of the power source, and a substrate is placed in the sputtering chamber. Argon gas with a flow rate of 20 sccm is passed, and the sputtering chamber is operated at a DC power of 100 W to 1500 W. The sputtering process was performed while maintaining a vacuum of 5 mtorr.

Next, gradually increase the sputtering power within the aforementioned DC power range, and observe whether the welding failure of the target body and the backing tube occurs at the specific sputtering power of the rotating target, causing the target body to fail to follow the backing tube. Rotate together or the target ruptures. When the above conditions are observed, the DC power applied at that time is recorded. The area of the DC power relative to the target 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 it is the ceramic rotating target material of Example 1 or the metal rotating target material of Example 2, the graphite blanket and conductive thermal conductive adhesive are used as the material of the joint. The rotating target materials of Examples 1 and 2 are spattered. The maximum withstand power during plating is greater than the maximum withstand power of the rotating targets in Comparative Examples 1 to 6 during sputtering, showing that the resistance to sputtering power of the rotating targets in Examples 1 and 2 is significantly better than that of the comparative examples. Sputtering power tolerance of the rotating targets of 1 to 6; in particular, the maximum withstanding power of the rotating targets of Examples 1 and 2 during sputtering is significantly greater than that of the rotating targets of Comparative Examples 1 and 2 during sputtering Maximum withstand power at the time.

In summary, this creation uses graphite blanket and conductive thermal adhesive as the material of the joint. Using this joint to join the hollow target and the backing tube can not only take into account the joint strength of the two, but also greatly increase the joint strength. Improving the sputtering power tolerance of the rotating target, while helping to increase the sputtering efficiency of the rotating target, extending the life of the rotating target, and even giving the creative rotating target a superior development potential.

The above embodiment is only an illustration for explaining this creation, and does not limit the scope of rights claimed by this creation in any way. The scope of the rights claimed in this creation should be based on the scope of the patent application, and not limited to the specific embodiments described above.

10‧‧‧backing tube
20‧‧‧ Hollow Target
30‧‧‧Joint
A‧‧‧Assembly auxiliary tools
D1‧‧‧ Outside diameter
D2‧‧‧Inner diameter
F‧‧‧Rally

Fig. 1 is a schematic diagram of the joining of the backing tube and the joint to the target body by using an assembly assisting tool when producing the rotating targets of Examples 1 and 2 and Comparative Examples 5 and 6. Fig. 2 is a cross-section of the rotating target A schematic view of the structure; and FIG. 3 is a schematic cross-sectional view of a test piece used for a shear tensile test.

10‧‧‧backing tube

20‧‧‧ Hollow Target

30‧‧‧Joint

D1‧‧‧ Outside diameter

D2‧‧‧Inner diameter

Claims (10)

A rotating target material includes a target body, a backing pipe, and a joint member. The joint member is disposed between the target body and the backing pipe, and the joint member includes a compressible structure and a conductive material. Thermally conductive adhesive, the compressible structure is a compressible blanket or a compressible sheet. The rotating target according to claim 1, wherein the joint member is formed of a compressible structure to which the conductive thermal adhesive is adsorbed. The rotating target material according to claim 1, wherein the compressible structure is a graphite blanket, a graphite sheet, a carbon blanket, a carbon sheet, a metal wire, or a combination thereof. The rotating target material according to claim 1, wherein the thermal conductivity of the joint is greater than 20 W / m. The rotating target material according to claim 1, wherein the resistivity of the joint is less than 5 x 10 ^-3 Ω˙cm. The rotating target material according to claim 1, wherein the conductive and thermally conductive adhesive of the joint member is composed of a thermosetting resin. The rotating target material according to claim 1, wherein the conductive thermal adhesive of the joint comprises a plurality of conductive particles and a thermosetting resin, and the content of the conductive particles is 10% by volume to 60% by volume. The rotating target material according to claim 7, wherein the conductive particles are aluminum particles, gold particles, silver particles, copper particles, zinc particles, iron particles, nickel particles, or a combination thereof. The rotating target material according to any one of claims 1 to 8, wherein the target material system is made of a ceramic material, a metal material, or a composite material. The rotating target material according to any one of claims 1 to 8, wherein the material of the backing pipe is copper, a copper-containing alloy, an aluminum alloy, titanium, or stainless steel.