JPH02133557A - Manufacture of copper base material for vacuum vapor deposition - Google Patents

Abstract

PURPOSE:To manufacture an oxygen-free Cu base material for vacuum vapor deposition by casting high-purity Cu in a nonoxidizing atmosphere, working the above into the desired shape, etching the surface of the above with acid, and successively subjecting the above to immersion into an alcohol solution of hydroxylamine, to drying, and then to vacuum packing treatment. CONSTITUTION:Electrolytic copper of >=99.99% purity is cast in a reducing atmosphere of CO gas, H2 gas, etc., or in vacuum, worked into chip shape, and then immersed into strong acid, such as nitric acid, by which the surface is etched to >=50mum thickness and a Cu2O film on the surface is removed. Subsequently, the above Cu is immersed into an alcohol solution of hydroxyl of >=2wt.% concentration, dried in an oven of <=80 deg.C, and subjected, without delay, to vacuum packing treatment. By using O2-free Cu as the raw material at the time of forming a thin Cu film by a vacuum vapor deposition method, a vapor- deposited film of high-purity Cu free from surface defects can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The method of the present invention relates to a method for producing a copper substrate for forming a copper thin film, which is used for vacuum deposition.

"Conventional technology" Recently? There is a strong tendency to use thin copper films for 7ri electrodes in X-ray devices, and it is becoming more and more useful to produce this type of copper thin film by the vacuum evaporation process. In this step of forming a thin copper film by vaporizing,
Various surface defects, especially protruding surface defects, may occur on the blue surface 1-, and the problem is that the occurrence of these surface defects makes it difficult to increase the repair rate or reduce the yield in the forming process. Kaa-).

In order to prevent the occurrence of surface defects, it is effective to form the copper bracket from high-purity copper with a low content of impurity elements. Effective.

Therefore, conventionally, in the manufacturing method of copper scrap material for vacuum deposition,
In order to reduce the oxygen content, methods have been implemented in which copper is melted and cast in a monotonous gas atmosphere or a vacuum atmosphere.

``Problem to be solved by the invention'' However, when the oxygen content is low at the stage of melting and casting, and when processing is performed after casting, the surface of the copper base material often changes during the processing process to the final shape. There is a problem in that copper oxide (Cute) is produced by oxidation, and the production of copper oxide causes protruding surface defects in the step of forming a copper thin film by vacuum evaporation. Furthermore, in order to solve the problem described in item nj, if the surface part of the oxidized copper base material is cut and removed, the yield of the copper base material using high-purity copper will deteriorate and the manufacturing cost will increase significantly. There is a point.

Furthermore, if a copper base material from which the oxidized surface portion has been removed is left in the atmosphere after cutting, there is a problem in that copper oxide is generated on the surface again.

In addition, in the past, after machining to the final shape, in order to remove dirt adhering to the surface of the copper substrate, it was washed with water or alcohol, and then dried with hot air using a dryer, etc. During the drying process, there was a problem in which atmospheric dust was blown onto the copper base material, causing the copper base material to become dyed and reducing its purity. In some cases, there is a problem in that protrusion-like surface defects occur on the copper thin film.

Because of the problems described above, the inventors of the present invention left oxygen-free copper chips in the atmosphere for a long period of time, and removed the copper base material, which had discolored due to the formation of copper oxide, without cutting the surface. When etched to an appropriate thickness, the copper oxide was removed and the discoloration disappeared. When immersed in an alcoholic solution of hydroxylamine with an appropriate concentration and dried in an atmosphere at an appropriate temperature, the copper oxide was removed again. It has been found that this substrate is difficult to form, and that no surface defects occur in the deposited film formed using this substrate.

The present invention has been made based on the above findings, and an object of the present invention is to provide a copper base material for vacuum evaporation that can stably obtain a copper evaporation surface that does not cause surface defects when used for vacuum evaporation. do.

"Means for Solving the Problems" The present invention uses copper with a purity of 99.99% or more as a raw material.
Forming a copper casting by casting in a reducing gas atmosphere such as O gas, H gas, or in a vacuum atmosphere,
After processing this cast product, the surface of this processed product is immersed in an acid such as nitric acid to create an edging with a thickness of 507 mm or more and then removed. After soaking in an alcohol solution of 80
The product is dried in an atmosphere at a temperature below °C, and the dried product is vacuum packed.

In this invention, the purity of copper as a starting material is set to 9999% or higher.If the purity is less than 9999%, there will be too many impurities, so if the copper base material is formed by carrying out the method of the present invention,
This is because surface defects occur in the 7A n film formed from the copper base material. Furthermore, if the etching depth is less than 50 μm, copper oxide (CuyO) cannot be removed for 1 minute, and surface defects are likely to occur in the deposited film. However, excessive etching deteriorates the yield of the copper base material, consumes a large amount of etching solution, and causes an increase in manufacturing costs, so it is preferable that the etching thickness be as small as possible.

On the other hand, the reason why the concentration of hydroxylamine is set to 2% or more is to sufficiently neutralize the free acid since copper oxide is likely to be generated when the free acid adheres to the surface of the copper base material. Furthermore, immersion in an alcoholic solution of hydroxylamine after etching has the effect of removing this free acid and making it difficult for copper oxide to form on the surface of the copper substrate. However, if the degree of oxidation of hydroxylamine is 2% or less, the effect of making it difficult to form copper oxide is insufficient. Furthermore, when the copper base material is dried in an atmosphere at a temperature of 80° C. or lower, no copper oxide is generated on the surface of the copper base material. Note that the acid used for the etching may be nitric acid or the like.

Furthermore, vacuum packing processing involves covering the processed product with a plastic film, evacuating the inside with a vacuum pump, making the Plus Deck film adhere to the processed product, and welding the edges of the plastic film to integrate the processed product with the plastic film. This is a complete packaging process. By carrying out this vacuum packing process, high quality copper base materials manufactured such as Jyuren can be stored for a long period of time without being oxidized.

"Function" By using copper with a purity of 99.99% or more as a raw material, impurities are reduced and a high quality copper base material can be obtained. In addition, the copper oxide portion on the surface should be sufficiently removed by making the etching depth deeper than 50 μm.

In addition, by dipping in an alcoholic solution of hydroxylamine with a concentration of 2% or more after acid oxidation, the remaining diacid is neutralized. In addition, there are five methods for vacuum drilling and drilling.
The high quality copper base material can be stored for a long time without oxidation.

[Example 1 Using 9999% pure jiX copper decomposition as a starting material, up to 1 total α
Sky! ! In a vacuum atmosphere of t l Obtained.

Next, this oxygen-free copper rod was subjected to machining such as swaging to obtain a chip having a diameter of 101!1111 and a length of 101. Furthermore, soak this chip in nitric acid and remove it from the surface.
Etching treatment was performed to dissolve and remove the 0 μm portion.

Subsequently, it was immersed in an ethanol solution of 2% human [1-xylamine] and then dried in an oven at 80°C.

Then, immediately apply vacuum treatment to the dried items with a plastic sheet! Leave it in the air at room temperature for 10 days, then take it out and remove it from the sample (again.

The sample obtained as above was used as a copper base material.
1l) Vacuum level reached on s substrate I X I O”Torr
A thin copper pattern was formed by dry vapor deposition under the following conditions, and the vapor-deposited surface was observed under a microscope to check for surface defects such as protrusions (projections of 05 μm or larger). An equivalent test was carried out using the samples produced in Comparative Examples 1 to 6.
The results are listed in Table 1 below.

"Comparative Example 1" In the 6th treatment of the above-mentioned Example, only the vacuum tsukku treatment was omitted, and the dried product obtained by Ike no Mori in the same article i++) and j-) was left in its original state. The sample was prepared by leaving it for 90 minutes at room temperature.

[Comparative Example 2-1 A sample was prepared under the same conditions as in the Example described in JFJ, except for t1, which was immersed in a 2% concentration hydroxylamine ethanol solution and dried in an oven at 100°C.
did.

1-Comparative Example '3'' A 1% concentration hydroxylamine ethanol solution was
The other conditions were the same as in the above-mentioned practical example, and a sample was prepared under 0) t't. .

[Comparative Example 4j The etching depth with nitric acid was set to 30 μm12, and the other conditions were the same as those in +1ii. Test v1 was prepared using copper as the starting material (L), and other conditions were the same as those in the previous example.

"Comparative Example 6" @ A copper chip of a tough bift copper rod (diameter 20 mm x length 300 o + m) with a cumulative content of 350 ppm was made,
Other treatments were carried out in the same manner as in the above-mentioned practical example to prepare a sample.

Table 1 As is clear from Table 1, the present invention has an excellent copper base ( It turned out that it was possible to manufacture ``.

1 Effect of the invention-1 As explained above, according to the present invention, pure IJ%: 99
The raw material is copper with less impurities of 99% or more, and is cast in a reducing gas or vacuum atmosphere to prevent oxidation during the casting process, and the surface of the processed product is coated with acid to a thickness of 50 μm.
The surface of the processed product is sufficiently reduced with an Alfur solution of hydroxylamine with a concentration of 2% or more, so when used for vacuum deposition, the surface of the processed product can be removed without surface defects. High quality copper base that can be formed (4
It has the effect of allowing you to use iQ. In addition, the purity is 99.9
By using #9"4-Lo') #14 as a raw material, the influence of impurities is removed, and by etching it to a depth of 50 μm or more, the copper oxide formed on the surface of the processed product is sufficiently removed. By treating with an alcohol solution of hydroxylamine with a concentration of 2% by weight or more, the acid on the surface is neutralized, and by drying in an atmosphere at a temperature of 80°C or less, the surface will not be oxidized during drying, so the final result is A high-quality copper base material can be obtained. Furthermore, by vacuum-backing the high-quality copper base material obtained as described above, its quality can be maintained for a long period of time.

Claims (1)

[Claims] CO gas, H
A copper casting is formed by casting in a reducing gas atmosphere such as _2 gas or in a vacuum atmosphere, and after processing this casting, the surface of the processed product is dipped in acid and etched to a thickness of 50 μm or more and removed. Copper for vacuum evaporation, which is further immersed in an alcoholic solution of hydroxylamine with a concentration of 2% by weight or more, dried in an atmosphere at a temperature of 80°C or less, and subjected to vacuum packing treatment to the dried product. Method of manufacturing base material.