Sunnyvale-based Spansion, a developer of flash memory products, said Sunday that it has filed for Chapter 11 bankruptcy protection. Spansion--which just laid off 3000 employees on Wednesday--said the move is part of a strategy to "strengthen its financial position," and in particular, to allow it to restructure its "burdensome" debt obligations. Spansion said all of its subsidiaries have also filed for Chapter 11. The firm said it will look to gain a "debtor-in-posession" credit facility. Spansion is a maker of flash memory products, used in cell phones and other products. The bankruptcy filing came after the firm failed to make interest payments on its bonds.