used as the plating solution ag cl will have an adverse effect on the plating and will be concentrated in the film it is desirable that the content of alkali metals such as na k and alkaline earth metals such as ca mg in the high purity copper sulfate is 1 wtppm or less respectively this is because when copper sulfate is to be used as the plating solution in the manufacturing method of a semiconductor device it is easily engulfed in the plating coating and will have an adverse on the performance of the semiconductor further it is desirable that the amount of si containing oxide and based on si conversion in the high purity copper sulfate is 10 wtppm or less this is because it will become foreign matter in the plating coating the flow of the manufacturing method of high purity copper sulfate according to the present invention is shown in the fig1 examples of the present invention are now explained incidentally these examples are merely illustrative and the present invention shall in no way be limited thereby in other words the present invention shall include within the scope of its technical spirit any and all modes or modifications other than the examples of this invention 250 g of commercially available copper sulfate cu 2 so 4 5h 2 o having a purity level of 99 9 wt containing the impurities shown in table 1 was dissolved in 1000 ml of purified water at room temperature next this was heated at 90 u00b0 c to evaporate water in a prescribed amount next this was cooled to room temperature the initial crystals were precipitated and subject to filtration the relationship of the amount of filtration solution and the weight of initial crystals as.