PORTLAND, Ore. (AP) ¿ Zygo Corp. will pay a $5.4 million break-up fee to terminate a merger agreement with suitor Electro Scientific Industries Inc., after the value of the all-stock deal declined amid the weaker market. Zygo, based in Middlefield, Conn., will be required to pay another $1.2 million if its board approves another deal to sell its businesses in the next six months. Zygo makes optical components, inspection and measurement equipment and automation systems. Electro, which makes test equipment for semiconductor makers, had agreed to buy Zygo in October in an all-stock deal worth about $173.6 million, or $10.30 per share, at the time. But because Electro's shares have since declined, the deal is now worth about $105.9 million, or $6.29 per share, based on Zygo's 16.8 million outstanding shares as of Nov. 3. Zygo shares rose 55 cents to close earlier at $5.05, while Electro Scientific shares closed up 69 cents at $6.71.