SAN JOSE – Bookings at North American-based semiconductor equipment manufacturers rose 39% to $1.7 billion in January. The book-to-bill jumped to 1.06, the SEMI trade group said, rising for the third straight month and closing above the benchmark 1.0 level. 

The sums are based on a three-month average of worldwide bookings.

Bookings rose 14% sequentially, and 39% year-over-year.

January shipments were $1.62 billion, up 9% from December 28% over last year. 

"Bookings and billings for semiconductor manufacturing equipment from North American-based companies increased as global memory chip makers sustained investments in the period," said Stanley T. Myers, president and CEO of SEMI.

The SEMI book-to-bill is a ratio of three-month moving averages of worldwide bookings and billings for North American-based semiconductor equipment manufacturers.

A book-to-bill of 1.06 means that $106 worth of orders were received for every $100 of product billed for the month. A ratio over 1.0 is considered a sign of expansion.