JPH0379734A - Copper alloy for backing plate - Google Patents

Abstract

PURPOSE:To reduce the deformation in the copper alloy caused by thermal strains, to permit its repeated use and to make better its heat conductivity and brazability by incorporating a copper alloy with a specified amt. of Cr as essential components. CONSTITUTION:The compsn. of a copper alloy for a backing plate used for sputtering is formed from, by weight, 0.05 to 0.8% Cr and the balance Cu with inevitable impurities. More preferably, one or more kinds among 0.01 to 2.5% Sn, 0.01 to 1.0% Zn, 0.01 to 0.3% Si, 0.01 to 0.3% Zr, 0.001 to 0.5% Mg, 0.01 to 1.0% Te and 0.1 to 4.0% Pb are furthermore incorporated thereto. In this way, the number of times in its use till the time when it can not be used caused by thermal strains comes to about >=2 times compared to that in conventional oxygen free copper as well as its brazability is made better. In addition, the evaporation of harmful elements is eliminated and normal sputtering can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a copper alloy suitable for a backing plate used in sputtering.

(Prior art) In recent years, there has been a rapid increase in demand for highly functional thin films for transparent conductive electrodes, optical and magnetic memory elements, semiconductor devices, etc.Many of these thin films use target materials tailored to their respective purposes. It is created by sputtering method.

Such a target material is normally used by being fixed to a backing plate by a method such as soldering.

However, because of the need to hold and cool the material, the material for the backing plate has characteristics such as not being deformed by heat effects during sputtering, good thermal conductivity, and good solderability. is required. For this reason, oxygen-free copper, which has excellent thermal conductivity, has conventionally been used for backing plates.

(Problem to be solved by the invention) However, in recent years, as target materials have become larger, thermal distortion during sputtering has become larger, and as a result, oxygen-free copper backing plates deform during sputtering, making it difficult to use them repeatedly. This has become difficult.

Therefore, in view of the above-mentioned problems, the present invention has developed a copper alloy suitable for use in a backing plate, which has little deformation due to thermal distortion, can be used repeatedly, and has good thermal conductivity and soldering. is intended to provide.

(Means for Solving the Problems) In order to achieve the above object, the inventors have made various studies and have arrived at the present invention.

That is, the first copper alloy for a backing plate of the present invention is characterized by consisting of 0.05 to 0.8% Cr (hereinafter, % by weight is simply referred to as %), the balance being Cu and inevitable impurities. , the second backing plate copper alloy is . Contains 0.05 to 0.8% of Cr, and further contains 0.05 to 0.8% of Sn.
01-2.5%, Zn 0.01-1.0%, Si 0
．． 01~(>,3%, ZrD, 01~0.3%,)
IQo, 001~0.5%, Te 0.01~1.0%
, Pb0.1 to 4.0%, including more than ■ species, the remainder C
It is characterized by consisting of u and inevitable impurities.

(Function) Next, the reason for adding the alloy components constituting the alloy of the present invention and the reason for limiting the composition range will be explained.

Cr in the first invention is dispersed as precipitates in the alloy, thereby increasing the alloy strength without significantly reducing thermal conductivity, and working to suppress deformation due to thermal strain to a small extent.
The Cr content was 0.05% to 0.8%.
If it is less than 0.8%, the effect will not be sufficient, and if it exceeds 0.8%, a coarse Cr phase will appear and the brazing strength will deteriorate.

Cr in the second invention is as described in the t-th invention, and Sn improves the dispersion state of Cr precipitates and at the same time improves the alloy strength by being dissolved in the alloy itself and deforms due to thermal strain. However, the reason why the sn content is set at 0.01 to 2.5% is that if it is less than o or oi, the effect will not be sufficient, and if it exceeds 2.5%, the thermal conductivity will decrease. This is because the decrease becomes significant. Next, In improves the castability of the alloy, but the content of 2n is reduced to o, oi ~ 1,0%.
The reason for this is that if it is less than 0.01, the effect will not be sufficient, and if it exceeds 1.0%, the strength of the soldered column will deteriorate. Si and Zr improve alloy strength and suppress deformation due to thermal strain, but the content of each should be reduced from 0.01 to 0.3.
% because if it is less than 0.01%, the effect will not be sufficient, and if it exceeds 0.3%, the effect will be saturated and the brazed column will deteriorate. Hg improves the alloy strength and suppresses deformation due to thermal strain, but the reason why the HQ content is 0,001 to 0.5% is because if it is less than 0.001, the effect is not sufficient. On the other hand, if it exceeds 2.5%, the castability of the alloy will deteriorate significantly. Te, Pb
Each works to improve the free machinability of the alloy, but Te
and pb content of 0.01 to 1.0%, 0,
The reason why it is set at 1 to 4.0% is that if it is less than a predetermined amount, the effect will not be sufficient, whereas if it exceeds a predetermined amount, the effect will be saturated and it will be difficult to manufacture the alloy.

(Example> Examples will be explained below.

Ordinary electrolytic copper is melted in the atmosphere in a high frequency melting furnace to produce 14g of Cr, Sn, In, Si, Zr, etc. according to the target value.
, Te, and Pb were added in the form of pure metals or a copper master alloy containing 10 to 50% of each, and an ingot with a thickness of 100 mm and a cross section of 11,400 mm was obtained by semi-continuous casting.

The composition of the obtained ingot is shown in Table 1. These ingots were heated to 850 to 950°C and then hot rolled into plates with a thickness of 15 mm. The plate thus obtained was placed in the atmosphere for 50 minutes.
After heating at 0℃ for 1 hour, the surface oxidation layer was reduced to 2.5nw on one side.
A test material with a plate thickness of 10 mm was obtained by side-facing the plate in n increments.

A brazing test and a sputtering test were conducted to evaluate the sample thus prepared.

First, the brazed column is 10mm x 10m from the above sample material.
A test piece of m x 50 mm was cut out, and after pickling and drying, the test piece was immersed in an In-10% Sn bath for 5 minutes, and evaluated by visually observing whether the wax was uniformly wetted on the surface.

Next, a sputtering test was performed on the above sample material.
After cutting a backing plate with a length of 444 m and a thickness of 10 mm, the actual width was 1301 WI,
ITO target with length 420 mm and thickness 5W11!・
And if the process of bonding the M~81 alloy target to the above backing plate using In-10% Sn brazing material and performing sputtering is repeated, how many times can it be used until it becomes unusable due to deformation due to thermal strain? was evaluated. However, sputtering requires a current of 10
~20A, 24H under test conditions of voltage 300~400V
It was carried out in a batch operation of r. In addition, the deformation limit due to thermal distortion of the backing plate is determined by placing the used backing plate on a surface plate, and setting the maximum dimension of the part that has risen due to bending, twisting, etc. to be 5 mm, and anything exceeding this value cannot be used. did.

These results are shown in Table 1 together with the results of comparative alloys produced and evaluated in the same process.

As shown in Table 1, the alloy according to the present invention can be used more than twice as many times before becoming unusable due to deformation due to thermal strain compared to the conventional oxygen-free copper material, and also has good solderability. It is clear that this is the case. Furthermore, as a result of sputtering tests, the alloy according to the present invention has a thermal conductivity of 0.
．． 2 Ca17'cn.sec.degree. C. or higher, which poses no practical problems, and it has also been revealed that there is no evaporation of harmful elements and normal sputtering can be performed.

<Effects of the Invention> As is clear from the above, according to the present invention, it is possible to provide a material suitable for a backing plate used in sputtering, and the industrial value of the present invention is great.

Claims (2)

[Claims] 1. A copper alloy for a backing plate characterized by comprising 0.05 to 0.8% by weight of Cr, the balance being Cu and unavoidable impurities. 2. Contains 0.05 to 0.8% by weight of Cr, and further contains 0.05 to 0.8% of Sn.
01-2.5% by weight, Zn0.01-1.0% by weight, S
i0.01-0.3% by weight, Zr0.01-0.3% by weight, Hg0.001-0.5% by weight, Te0.01-1
．． A copper alloy for a backing plate, characterized in that the copper alloy contains one or more of 0% by weight and 0.1 to 4.0% by weight of Pb, the balance being Cu and inevitable impurities.