| 摘要 |
PROBLEM TO BE SOLVED: To obtain a heat bonding sheet capable of sufficiently relaxing the thermal stress between a semiconductor element and a wiring circuit board and preventing cracks from occurring and excellent in reliability of electrical connected parts by providing the sheet with respective specific moduli of elasticity at respective prescribed temperatures. SOLUTION: This sheet 3 is provided with characteristics of (i) <=10 MPa modulus of elasticity at 250 deg.C and (ii) <=2,000 MPa modulus of elasticity at -80 deg.C. Furthermore, the heat bonding sheet 3 is preferably composed by forming heat bonding layers 1 formed by using a thermoplastic polyimide such as a silicone-modified polyimide represented by formula I [R1 is represented by formula II or the like; R2 is C3H6, C4H8 or the like; n is 1-100; (a) and b satisfy the relationship of (a+b)=1 and further satisfy the relationship of 0.3<=(a)/(a+b)<=0.99] on at least one surface of a sheetlike porous substrate 2, which is preferably a porous sheet made of polytetrafluoroethylene. |
