TW201711983A - Solder for fabricating sputtering target and applying method thereof - Google Patents

Abstract

A solder used for bonding a target material with a backing plate when producing sputtering target, wherein the solder contains zinc (Zn) 8% to 9% by weight, tin (Sn) 81% to 91.5% by weight and indium (In) 0.5% to 10% by weight, wherein a sum of Sn and In is less than and equal to 91% by weight.

Description

Solder for sputtering target and application method thereof

Embodiments of the present invention relate to a solder for making a sputter target and a sputter target using the solder. In particular, there is a solder containing indium (In) and a sputtering target using the solder.

The thin film sputtering technique uses a pulsed direct current plasma to bombard the surface of the metal target, and the target atom is struck and sputter deposited on the surface of the target substrate to form a thin film, which has the advantages of high quality, good adhesion, excellent process stability, and the like, and can be used for the film sputtering method. Coating of plastic, metal, glass, cloth or composite materials.

Since the sputtering process causes the target to generate a large amount of thermal energy accumulation, a metal backing plate having a good thermal conductivity, such as a copper (Cu) backing plate or a copper alloy backing plate, is used to bond with the target. Thereby, the heat of the target is dissipated and the target is cooled. If the bonding strength between the target and the backing plate is not good, or the thermal conductivity of the interface is poor, the target temperature will rise rapidly during the sputtering operation. Problems such as delamination of raw weld, melting of backing plate or overheating of equipment.

Conventionally, indium (In) having a low melting point has been generally used as a solder to bond a target to a back sheet. However, since indium is expensive, and it is prone to hot warp when applied to a large-area target, it is easy to peel the target from the back sheet due to poor joint strength at high temperature operation.

Therefore, there is a need to provide an advanced solder and a sputtering target using the solder to solve the problems faced by the prior art.

According to an embodiment of the present invention, a solder is provided for bonding a target layer to a backing plate to form a sputtering target, the solder comprising: a weight percent concentration (%) substantially between 8 and 9 Zinc (Zn), tin (Sn) having a weight percentage substantially between 81 and 91.5, and indium (In) having a weight percent concentration substantially between 0.5 and 10, and the sum of the contents of tin and indium is less than or equal to the weight percent concentration 91.

Another embodiment of the present invention provides a sputtering target comprising: a target layer, a backing plate, and solder for bonding the target to the backing plate. Wherein the solder comprises zinc in a concentration of substantially 8 to 9 by weight, tin in a concentration of substantially 81 to 89 by weight, and indium (In) in a concentration of substantially 0.5 to 2, and tin and indium. The sum of the contents is less than or equal to the weight percent concentration of 91.

Yet another embodiment of the present invention provides a method of fabricating a sputtering target, comprising the steps of: providing a solder comprising a zinc having a weight percent concentration substantially between 8 and 9 and a weight percent concentration substantially Tin from 81 to 89 and The weight percent concentration is substantially between 0.5 and 2 indium, and the sum of the tin and indium contents is less than or equal to the weight percent concentration of 91. Next, a solder is applied between the backing plate and the target layer. Subsequently, a press-bonding process is performed to bond the backing plate and the target layer by solder.

In light of the above, embodiments of the present invention provide an alloy solder using a specific weight percent tin-zinc-indium composition to bond a target layer to a backing plate to form a sputtering target. Such an alloy solder maintains the bonding strength between the target layer and the back sheet under large-area and high-temperature sputtering conditions, and prevents the target layer from being peeled off from the back sheet. The content of indium in the solder can be reduced to substantially equal to or less than 10% by weight, which greatly reduces the manufacturing cost of the sputtering target. The problems faced by the prior art can be solved by taking into consideration the strength, thermal conductivity and temperature resistance of the sputtering target, ease of operation, and cost.

The present invention provides a solder and a sputtering target made using the solder, which can solve the problem that the conventional sputtering target is expensive to manufacture, is difficult to apply in a large area, and is prone to hot warp. The above and other objects, features and advantages of the present invention will become more apparent and understood.

But it must be noted that these specific implementation cases and methods, and It is not intended to limit the invention. The invention may be practiced with other features, elements, methods and parameters. The preferred embodiment is presented merely to illustrate the techniques of the present invention. Features are not intended to limit the scope of the claims of the present invention. In the technical field Equivalent modifications and variations will be apparent to those skilled in the art without departing from the scope of the invention.

According to an embodiment of the invention, a solder is provided for bonding a target layer to a backing plate when the sputtering target is manufactured. Wherein the solder comprises zinc (Zn) having a weight percent concentration substantially between 8 and 9, a tin (Sn) having a weight percent concentration substantially between 81 and 91.5, and indium having a weight percent concentration substantially between 0.5 and 10. In), and the sum of the contents of tin and indium is less than or equal to the weight percent concentration of 91. In other words, the solder consists essentially of a tin-zinc-indium alloy.

In one embodiment, the solder of the present invention comprises zinc (Zn) having a weight percent concentration substantially between 8 and 9, a tin (Sn) having a weight percent concentration substantially between 83 and 91, and a substantial concentration by weight 1 to 8 indium (In).

In one embodiment, the solder of the present invention comprises zinc (Zn) having a weight percent concentration substantially between 8 and 9, a tin (Sn) having a weight percent concentration substantially between 86 and 91, and a substantial concentration by weight 1 to 5 indium (In).

In one embodiment, the solder of the present invention comprises zinc (Zn) having a weight percent concentration substantially between 8 and 9, a tin (Sn) having a weight percent concentration substantially between 88 and 91, and a substantial concentration by weight 1 to 3 indium (In).

In one embodiment, the solder of the present invention comprises a weight percent concentration substantially between the solder comprising a weight percent concentration of substantially between 8.5 and 9 zinc, weight percent rich Tin having a substantial concentration between 89 and 90, and indium having a weight percent concentration substantially between 1.5 and 2.

In one embodiment, the weight percent concentration of zinc in the solder of the present invention is substantially 9, the weight percent concentration of tin is substantially 89, and the weight percent concentration of indium is substantially 2.

Additionally, in some embodiments of the invention, the solder may also contain minor amounts, such as less than 0.5% of other elements. For example, aluminum, titanium (Ti), molybdenum (Mo), tantalum (Ta), niobium (Nb), copper, chromium (Cr), silver (Ag), cerium (Si), and rare earth elements, the rare earth element is selected from Yu, La, Ce, Pr, Nm, Pm, Sm, Eu, Gd, Tb, Dy , 鈥 (Ho), 铒 (Er), 銩 (Tm), 镱 (Yb), 镏 (Lu), 钇 (y), 钪 (Sc) and any combination of the above.

In some embodiments of the invention, the target layer can be a metal target layer. In an embodiment, the target layer can be an aluminum (Al) containing target layer. In an embodiment, the target layer can be a copper (Cu) containing target layer. The backsheet is preferably a copper (Cu) containing backsheet, such as a copper backsheet or a copper alloy containing backsheet.

In one embodiment, the temperature at which the metal target layer and the copper-containing backsheet are joined using the solder alloy of the present invention is substantially between 180 ° C and 220 ° C. In one embodiment, the temperature at which the aluminum-containing target layer and the copper-containing backsheet are joined using the solder alloy of the present invention is substantially between 180 ° C and 220 ° C.

Since the solder alloy contains tin in a concentration of substantially 81 to 91.5 by weight, high bonding strength between the metal target layer and the copper-containing backing plate can be maintained at a high temperature. For example, at a temperature of 150 ° C, the joint strength between the aluminum-containing target layer and the copper-containing back sheet can be substantially 2.5 kgf/mm ² or more, preferably 3.0 kgf/mm ² .

In addition, since the solder alloy contains zinc in a concentration of substantially 8 to 9 by weight. It inhibits the reaction of tin in the solder alloy with the copper element in the copper-containing backsheet, reduces the corrosion that may occur during bonding, and improves the wettability of the solder alloy to tightly bond the solder to the copper-containing target.

The method of bonding a metal target layer to a copper-containing backsheet to form a sputtering target comprises the steps of first surface-treating the joint surface of the metal target, for example, roughening, and washing and degreasing. Then, the metal target is heated to a temperature equal to or higher than the melting point of the solder alloy, and the solder alloy is applied to the joint surface of the metal target by a dipping method to form a bonding layer. Considering the sheet resistance of the solder alloy, the thickness of the bonding layer is substantially 2 mm or less, preferably substantially between 0.1 and 1 mm.

At the same time, the joint surface of the copper-containing back sheet is degreased and heated to a temperature above the melting point of the solder alloy, and then the joint surface of the copper-containing back sheet faces the joint layer, and then the three are pressed together. The pressure of the press is determined by the area of the metal target. In some embodiments of the invention substantially between 0.0001 and 0.1 MPa. In still other embodiments of the invention, the bonding layer may be applied to the bonding surface of the copper-containing backing plate, and the bonding surface of the metal target may be pressed against the bonding layer.

In the following, a number of specific examples will be given, and the comparison of the tensile strengths will be carried out in conjunction with the comparative examples to illustrate the technical advantages of the present case. First, a soft flux containing a tin/zinc/indium (Sn/Zn/In) weight ratio of 89:9:2 was prepared using tin having a purity of 99.99%, zinc having a purity of 99.99%, and indium having a purity of 99.99% as a raw material. (Solder alloy), which will be represented by Sn-Zn-2In soft solder.

Thereafter, the aluminum-containing target layer was bonded to the copper-containing backing plate using Sn-Zn-2In soldering agent to form a sputtering target, and three sets of sputtering targets were selected as the measurement samples of the examples, and the three groups were used with indium. A sputtering target made of a solder (In) was used as a comparative example to carry out a tensile strength test. In this embodiment, the tensile strength test is performed by bonding an aluminum-containing target layer having a bottom area of 10 mm×50 mm and a copper-containing backing plate having a size of 20 mm×20 mm×5 mm to form a sputtering target, and then using a tensile test. The apparatus of the above-mentioned sputtering target was measured at room temperature (23 ° C) by means of AUTOGRAPH AGS-500B (manufactured by Shimadzu Corporation (Japan)). The measurement results are shown in Table 1:

From the results of the tensile strength test, it can be found that the sputtering target bonded by Sn-Zn-2In soft solder has a tensile strength 32% to 98% higher than that of the sputtering target made of indium solder. . It is shown that the solder provided by the embodiment of the present invention is used to bond the aluminum target layer and the copper-containing back sheet to form a sputtering target, and the aluminum target layer and the copper-containing back sheet can be maintained under high temperature sputtering conditions. Bonding strength. Plus, welding The indium content used in the feed is quite low, helping to reduce manufacturing costs.

In light of the above, embodiments of the present invention provide an alloy solder using a specific weight percent tin-zinc-indium composition to bond a target layer to a backing plate to form a sputtering target. Such an alloy solder maintains the bonding strength between the target layer and the back sheet under large-area and high-temperature sputtering conditions, and prevents the target layer from being peeled off from the back sheet. The content of indium in the solder can be reduced to substantially equal to or less than 10% by weight, which greatly reduces the manufacturing cost of the sputtering target. The problems faced by the prior art can be solved by taking into consideration the strength, thermal conductivity and temperature resistance of the sputtering target, ease of operation, and cost.

While the invention has been described above in the preferred embodiments, it is not intended to limit the invention. The process steps and structures described herein do not encompass the complete fabrication process for making a full volume circuit. The present invention can be implemented in conjunction with a number of different integrated circuit fabrication techniques currently known or developed in the future. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

Claims (10)

A solder for bonding a target layer to a backing plate to form a sputtering target comprising: zinc (Zn) in weight percent (%) substantially in the range of 8 to 9 and weight Tin (Sn) having a concentration substantially between 82 and 91.5 and indium (In) having a weight percent concentration substantially between 0.5 and 10; and a sum of a content of tin and indium is less than or equal to a weight percent concentration of 91. The solder of claim 1, wherein the weight percent concentration of zinc in the solder is substantially 9, the weight percent concentration of tin is substantially 89, and the weight percent concentration of indium is substantially 2. The solder of claim 1, wherein the solder is used to bond a metal target layer to a copper (Cu) containing backsheet. The solder of claim 1, wherein the solder is used to bond an aluminum (Al) target layer to a copper (Cu) containing backsheet. A sputtering target comprising: a target layer; a backing plate; and a solder for bonding the target layer to the backing plate, wherein the soldering The material comprises a concentration by weight (%) of zinc substantially in the range of 8 to 9, a tin (Sn) having a concentration by weight of substantially 82 to 91.5, and an indium (In) having a concentration by weight of substantially 0.5 to 10, And the sum of the contents of tin and indium is less than or equal to the weight percent concentration of 91. The sputtering target according to claim 5, wherein the weight concentration of zinc in the solder is substantially 9, the weight concentration of tin is substantially 89, and the concentration by weight of indium is substantially 2. The sputter target of claim 5, wherein the target layer is a metal target layer; and the back sheet is a copper-containing back sheet. The sputter target of claim 5, wherein the target layer is an aluminum-containing target layer; and the back sheet is a copper-containing back sheet. A method of making a sputtering target, comprising: providing a solder comprising a weight percent (%) of zinc substantially in the range of 8 to 9, a weight percent concentration of tin (Sn) substantially between 82 and 91.5, and a weight of one hundred Indium (In) having a concentration substantially between 0.5 and 10, and a sum of a content of tin and indium is less than or equal to a weight percent concentration of 91; placing the solder between a backing plate or a target layer; and performing a pressing a process of bonding the backing plate and the target layer by the solder Engage. The method of producing a sputtering target according to claim 9, wherein the step of placing the solder between the backing plate or the target layer comprises: heating the backing plate or the target layer to the a melting point of the solder above the melting point; applying the solder to one of the backing plate and the target layer; and facing the other of the backing plate and the target layer.