求翻译：（2）选择材料时，对于PI为0.5和1mil的材料，可根据铜厚乘以0.7以上的系数选择胶厚，对于PI为2mil的材料，胶厚与铜厚比应该选择1.1以上才能兼顾填胶和可靠性两方面。是什么意思？

(2) when selecting materials, for PI is 0.5 and 1mil materials can be selected based on copper thickness multiplied by the coefficient of 0.7 per cent of rubber thick, for PI to 2mil material, rubber and thick and copper thickness ratio should opt for 1.1 per cent to take into account both glue-filling and reliability.