SEALING MATERIAL AND MOUNTING METHOD USING THE SEALING MATERIAL
A sealing material is provided, upon mounting semiconductor devices and/or electronic components which are relatively weak on a circuit board, which shows sealing characteristics that enables itself to seal the semiconductor devices and/or electronic components and connections therebetween with low stress and high reliability; and suitable repairability that enables merely semiconductor devices and/or electronic components which were determined to be off-specification after being sealed to be repaired with ease. The sealing material contains at least (a) a heat-curable resin component and (b) a hardener component therefor, and is characterized in that, once the sealing material is cured by being heated, the cured material has a glass transition temperature (Tg) in a temperature range of from −80° C. to 50° C.
1 - 10 . (canceled)
11 . A sealing material containing at least (a) a heat-curable resin component and (b) a hardener component therefor, wherein the heat-curable resin component is one or more resin components selected from the group consisting of an epoxy resin composition, an urethane resin composition, a phenol resin composition, which material can give, by being heated, a cured material which has a glass transition temperature (Tg) in a temperature range of from −80° C. to 50° C.
12 . The sealing material according to claim 11 , which contains no silicone resin.
13 . The sealing material according to claim 11 , which has a storage elastic modulus of 500 MPa or higher at a temperature range which is lower than the glass transition temperature (Tg) thereof and has a storage elastic modulus of 200 MPa or less at a temperature range which is higher than the glass transition temperature (Tg) thereof.
14 . The sealing material according to claim 11 , which has a storage elastic modulus of 800 MPa or higher at a temperature which is lower than the glass transition temperature (Tg).
15 . The sealing material according to claim 11 , which has a storage elastic modulus of 50 MPa or lower at a temperature which is higher than the glass transition temperature (Tg).
16 . The sealing material according to claim 11 , which has a storage elastic modulus of 10 MPa or lower at a temperature which is higher than the glass transition temperature (Tg).
17 . The sealing material according to claim 11 , which has the glass transition point (Tg) within the temperature range from −50° C. to 10° C.
18 . A method for mounting an electronic part on a circuit board, comprising:
(i) placing the electronic part at a predetermined position on the circuit board and forming an electrically conductive connection;
(ii) supplying the electrically conductive connection and the area around the connection with the sealing material according to claim 11 ; and
(iii) heating the board.
19 . A repairing method which comprises optionally heating a mounting-completed board which is given by the method according to claim 18 up to a predetermined temperature and pressing a tool to an area around a border between the board and the sealing material to cause substantial interface failure between the board and the sealing material, and removing the sealing material and/or the electronic part from the board.
20 . A mounted structure wherein an electronic part is placed at a predetermined position on a circuit board and an electrically conductive connection is formed between an electrode of the circuit board and a corresponding electrode of the electronic part, and the area around the connection and the space between the electronic part and the circuit board are sealed with the sealing material according to claim 11 .