Yeah. They make a huge percentage of the world's high-end chips. A military takeover would leave us shoveling piles of money at China or, more likely, the fabs would be destroyed and suddenly every computer or product that uses a computer to create it (read: all of them) shoots up in price for the next decade.
And that is just the immediate effects. The downstream effects of the US no longer providing security would likely lead to swift nuclear proliferation as that is the only way such a small country can hope to protect itself if no larger country is willing to stick their neck out for them.
There are companies and governments trying to put this right at the moment, but chip manufacturing capacity is very slow to set up. It requires very expensive, specialized and uncommon equipment and highly qualified specialist staff who are not easy to find or quick to train.