Mainly referenced to older computer systems.
Chip creep refers to the problem of chips that, over time, would work their way out of the socket. Chip creep occurred due to thermal expansion; the contracting and expanding during system heat up and cool down. While chip creep was most common with older memory modules it was a problem with other main chips that were inserted into sockets. To fix chip creep, users of older systems would often have to remove the case cover and push the loose chip back into the socket.
Today’s systems are not affected so much by chip creep since chips are mainly soldered into place or are more securely held by various types of retainer clips.