MILPITAS, Calif. (AP) ¿ Nanometrics Inc. said Thursday it has priced a public offering of new shares at $11 each, estimating net proceeds at $20.6 million. The price represents a nearly 12 percent discount to the stock's previous close at $12.44. Shares dropped $1.44, or 12 percent, to $11 in morning trading. The company, which makes semiconductor manufacturing equipment, is offering roughly 2 million new shares. In addition, founder Vincent Coates is selling 675,000 at the same price. The company expects to close the offering on or about Dec. 22. It plans to use $2 million of the proceeds to pay obligations related to acquiring assets from Zygo Corp., a Middlefield, Conn., company that makes optical components and fiber optic network equipment. The rest will go toward general corporate purposes, the company said. Over the past year shares of Nanometrics have traded as low as $1.05, in March, and at a peak of $14.06, earlier this month.