Attempts to impeach the President make news around the world - and the moves to impeach Nixon and Clinton are particularly memorable. But Article II Section 4 of the Constitution applies impeachment more widely - "The President, Vice President and all civil officers of the United States, shall be removed from office on impeachment for, and conviction of, treason, bribery, or other high crimes and misdemeanors." Judges have been held to come under the term "civil officers" and Art III says "The judges, both of the supreme and inferior courts, shall hold their offices during good behaviour".
There have been a number of impeachments of judges. CRS have produced a paper on Judicial Impeachment Proceedings which is available here.