By Juby BabuJuly 28 (Reuters) - KLA Corp on Tuesday beat fourth-quarter revenue estimates and forecast first-quarter revenue above Wall Street expectations, ‌but its shares fell 9% in extended trading as the ‌results failed to meet investor expectations. KLA provides process control and yield management systems, which are critical for identifying and correcting ‌defects during the semiconductor manufacturing ⁠process. Here are some ⁠details:• KLA's results and forecast were better than expected, but were not eye-popping by any means, CFRA analyst Brooks Idlet said. • KLA expects first-quarter revenue of $4 billion, plus or minus $200 million, ahead of analysts' average estimate of $3.92 billion, according to data compiled by LSEG. • The semiconductor equipment maker's fourth-quarter revenue ​grew 15.1% to $3.66 ‌billion, beating estimates of $3.60 billion.