BEIJING/TAIPEI -- Chinese President Xi Jinping's campaign to foster a self-reliant semiconductor industry has hit another obstacle as Taiwanese chipmaker United Microelectronics Corp. scales back cooperation with a Beijing-backed partner over tensions with the U.S.

"Semiconductors are like the human heart," Xi said while visiting chip producing companies in the Hubei Province capital of Wuhan last year. "No matter how big a person is, he or she can never be strong without a sound and strong heart," he said, urging businesses to make major breakthroughs that lift them to the top of the industry and contribute to the revival of the Chinese nation.

Wuhan is home to Yangtze Memory Technologies, a producer of 3D NAND flash memory and one of three chipmakers founded to promote the government's "Made in China 2025" initiative to cultivate high-tech industries. The other two are Innotron Memory, a producer of dynamic random access memory chips for mobile devices, and fellow DRAM maker Fujian Jinhua Integrated Circuit.

Xi had planned to accelerate projects from all three companies, but the future of multibillion-dollar investments by Fujian Jinhua, also known as JHICC, has turned murky.

U.S. memory company Micron Technologies accused UMC in 2017 of stealing corporate secrets for JHICC, suing the companies in California. UMC then brought Micron to court in China on allegations of copyright infringement.

The Fuzhou Intermediate People's Court ruled in favor of UMC in July and temporarily barred Micron from selling and producing certain products in China. The U.S. Justice Department then said in November that a federal grand jury indicted UMC and JHICC, as the legal battles take an increasingly political tinge.

UMC, fearing that the case will harm its main business of contract manufacturing, has decided to scale down its collaboration with JHICC.

JHICC was expected to begin mass chip fabrication based on UMC technology as early as 2019, but that scenario is extremely unlikely now. The company has not said whether new difficulties receiving UMC technology will impact its progress.

China aims to produce 70% of its own chips by 2025. The current figure, thought to be between 10% to 30%, leaves Chinese companies reliant on foreign chipmakers. Telecommunications equipment maker ZTE faced financial difficulties last year after the U.S. temporarily cut off its supply of American chips, forcing the company to reshuffle management.

Taiwan has been the most vital source of technology as the development of a semiconductor industry becomes imperative for Beijing. In addition to having high-tech expertise, the island shares a common language with the mainland. Taiwan already has handed over many chip designers to China, said Liu Pei-chen from the Taiwan Institute of Economic Research.

UMC has been the most cooperative of Taiwan's chipmakers. The company entered mainland China in the early 2000s when it invested in and transferred technology to HeJian Technology (Suzhou). Fearing technology leaks, Taiwanese authorities indicted UMC on charges of making illegal investments, but the chipmaker was found innocent and continued operations.

The Taiwanese company then jointly invested $6.2 billion in 2016 with the southeastern Chinese city of Xiamen and others to build a semiconductor factory there. UMC also said last year that it would list its Chinese subsidiary on a local exchange.

But trade tensions with the U.S. have forced the chipmaker to reconsider its China strategy, and the headwinds are blowing beyond JHICC.

American, European and Japanese semiconductor manufacturing equipment makers, having deemed deals with Chinese companies as high risk, seem to be growing hesitant about making shipments to Innotron and Yangzte Memory as well. China relies on these foreign players for such equipment and lacks domestic chip designers. This trend threatens to damage Xi's long-term vision for self-sufficiency.

In addition to semiconductors, the government has designated telecom equipment, robotics, aerospace, electric vehicles, new materials and biotechnology as priority fields in its Made in China 2025 plan and hopes to improve self-sufficiency in them as well.

But a global division of labor has developed among high-tech industries. China has been criticized for disrupting this balance through subsidies meant to encourage domestic production in these fields.

U.S. action to curb China's burgeoning high-tech industries now affects the activity of companies outside their borders. Trade tensions between the two countries are casting a long shadow on international specialization in these fields as well as technological advancement.