Samsung Electronics and SK Hynix are evaluating chipmaking equipment from China’s Advanced Micro-Fabrication Equipment (AMEC) for possible use at their Chinese factories, three people familiar with the matter said, as the South Korean companies hedge against the risk of tighter U.S. export controls.

The memory chipmakers began testing AMEC etching equipment about two years ago, when uncertainty was mounting over whether Washington would continue allowing them to import U.S. chipmaking tools into China, two of the sources said.

While the evaluations have yet to result in decisions on wider deployment, they offer the Shanghai-based company a rare chance to secure validation from some of the world’s leading chipmakers.