| abstract |
(57) [Problem] To be suitably used as a high-density packaging material such as a semiconductor package, a printed wiring board material such as a multi-layer flexible printed circuit board, and also an aerospace material. Provided is a bonding sheet having good adhesiveness, heat resistance, flexibility and processability. SOLUTION: The solid content concentration is 10% with respect to a low boiling point solvent such as 1,4-dioxane, 1,3-dioxolan and THF. A bonding sheet made of a resin composition containing a soluble polyimide and an epoxy resin that dissolves above and has high heat resistance and low water absorption, and has low water absorption, excellent solder heat resistance, and excellent heat resistance and adhesion. And a bonding sheet including an adhesive layer, which is made of a resin composition that can be bonded at a relatively low temperature, for example, 250 ° C. or lower. |