"(The company) has injected supplies other than Japanese imports in certain manufacturing processes," the Samsung official said, while speaking on condition of anonymity.
Another informed source said the company began using local supplies of etching gas.
Japanese imports are said to account for more than 90 percent of total supplies here for some of the three key materials.
Samsung, as well as its local rival SK hynix, began testing local supplies for their quality shortly after Japan announced its export curbs at the start of July, and market watchers earlier expected the tests to take up to six months.
Local industry leader LG Display earlier began using locally produced etching gas to produce display panels. (Yonhap)