All silver dollars made of silver contain 90% silver, but the last of those was minted in 1935. The Eisenhower dollars of the 1970s didn't contain silver.
If you go by the strict definition of "Liberty dollar" (i.e. a silver dollar made from 1794 to 1935) the answer is yes - these coins are 90% silver and 10% copper. But many people mistakenly call...
None of the coins released for circulation have any silver. People call them silver dollars just because of the size of the coins. Only special collectors coins sold from the Mint had any silver.