| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject film having a specific film thickness, containing a germanium compound and specific silicon dioxide particles in specific amounts, less in ionic impurity content and useful as the substrate of an adhesive tape used in a semiconductor production. SOLUTION: This biaxially stretched polyester film has 25-100μm film thickness, contains (A) 10-200ppm germanium compound (in terms of germanium element) such as germanium dioxide and (B) 0.01-2wt.% silicon dioxide particles (e.g. a synthetic material obtained by a wet or a dry method containing <=500ppm, especially <=50ppm of a metallic element other than silicon) having 0.001-5μm mean particle diameter and substantially not containing other metallic elements. |
