WASHINGTON, USA: North American manufacturers of equipment used to make semiconductors reported $569.7 million in orders in July, up 62 per cent from the previous month, reflecting a gradual recovery in demand for products such as mobiles and personal computers.

The book-to-bill ratio was 1.06 in July, meaning that $106 worth of orders were received for every $100 of product shipped, Semiconductor Equipment and Materials International (SEMI) said in a preliminary report.

The ratio is watched as an indicator of the demand pipeline for the industry, as well as for hints about chip capacity and whether the $300 billion semiconductor sector could be headed for a glut. July billings were $538.0 million, just over 22 percent up from June, and about 50 percent less than a year ago.

"The increases in both bookings and billings reported by North American equipment manufacturers boosted the book-to-bill ratio above parity for the first time since January, 2007," SEMI chief executive Stanley Myers said in a statement. "Even with that improvement, however, bookings remain significantly below year-ago figures," he added.

U.S. chip equipment makers include Applied Materials Inc, the world's biggest, testing tools firm KLA Tencor Corp, circuitry-etching tools company Lam Research Corp and Novellus Systems Inc, which specializes in preparing the surface of a silicon wafer before circuits are laid down.

The SEMI book-to-bill is a ratio of three-month moving averages of worldwide bookings and billings for North America-based chip-equipment makers.