SANTA CLARA, Calif. (AP) -- Applied Materials Inc. said Thursday it has launched its $364 million tender offer to buy all the outstanding shares of Montana-based Semitool Inc.

The chip manufacturing equipment maker is acquiring the company to tap the growing market for semiconductors that go into mobile gadgets including "smart" phones and notebook computers.

Applied Materials, based in Santa Clara, Calif., on Tuesday offered Semitool shareholders $11 per share, a 31 percent premium over Monday's closing share price of $8.40.

The offer is set to expire Dec. 17. Applied Materials must acquire more than two-thirds of the stock as well as receive regulatory approval for the deal to go through.

Kalispell, Mont.-based Semitool's board of directors has unanimously approved the offer and says it is in the best interests of shareholders.

Applied Materials shares fell 38 cents, or 3 percent, to close at $12.48 on Thursday. Semitool shares closed down 3 cents at $10.94.