I'm also sure they can go as far as 5nm like SMIC if they really wanted to, since it's strategic for China, but the cost would only be justified if the current cycle lasts long enough.
3D DRAM is no magic, it will only give them maybe 2 generations' breathing room if they got the required etching equipment figured out. But others will be doing 3D DRAM with EUV by then.
They are forbidden to buy foreign equipment beyond their current process node, which is already obsolete, die size is 40% bigger than Samsung, not to mention lithography, the big 3 are using EUV while they are stuck with lobotomized DUV.
They can start making some decent money now, but vastly expanding capacity as is means enormous losses if the cycle went downward a few years later, that's how all previous makers went bankrupt.
They can squeeze out a bit more performance if they are ready to go beyond their current node using only domestic equipment and be blacklisted by the US government.
But the cap is there, unless they can make a working EUV machine in 5 years, they are doomed to be a minor player, if the current cycle even lasts that long.
Dead Comment
It's currently selling its resources at a steep discount and that is unlikely to change because its customers are only in it for the bargain they're getting.
All these talk of cutting off Russia won't last more than a year after the war, nobody refuses cheap energy, certainly not the cash strapped Europeans.
They'll probably be the world leader in critical metals and rare earth deposits if they invested more on prospecting and the ice melts.
It already seems like Russia is positioned to be completely subservient to China in the future.
EU is now an unwilling dumping ground for China, hostility and paranoia are growing by the day now that China is no longer a lucrative market itself and is pursuing its interests outside commerce, the cordial days are numbered.
Russia would never be subservient to China, once the war ends Russia would be back being a geopolitical player because of its vast natural resources, and they are already import substituting even Chinese products.
Russia can turn to the west to be a real western country whenever they see fit, the eternal fear for China.
This is why China is going as far as it can to accommodate Putin, even souring it's relations with the EU which isolated itself.
In this sense, it is China being "subservient" to Russia.
It's all a sliding slope until it reaches a breaking point and falls off like a cliff.
EDIT: to quote the Canadian PN earlier today:
“American hegemony in particular helped provide public goods, a stable financial system... this bargain no longer works. Let me be direct. We are in the midst of a rupture, not a transition... recently, great powers have begun using economic integration as a weapon. Tariffs as leverage ..."
But doing that would undermine Euro's credibility, as the EU is a loose union of countries with their distinct interests and politics, also member countries would compete on outspending each other as the Euro would have been essentially free money, a Euro debt crisis on turbocharge.
So, the EU can never print like the US. The EU and China will be rivals.
People and news articles always talk about goods trade deficits for rich countries, but never their almost universal services trade surpluses, and the profit margins are vastly different.
For manufacturing, a large part of the revenue goes to materials costs, but for services, almost all of it are net incomes.
Yes you can bring back manufacturing jobs, but your services surpluses would also shrink, because when you don't open your market, countries were not obligated to let you reap profits there too.
The problem, however, is IO controller support has been dropped, many new CPUs don't even support DDR4 any more, especially mobile ones.