Patent ID: 11924979
Assignee: MITSUBISHI GAS CHEMICAL COMPANY, INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H  B  C  Y | IPC B  C  H

Claim 3:
4. The resin composition according to claim 1, wherein a contact angle of a solder ball obtained in the following solder wettability test using the chelating flux agent (A) is less than 1.20 radians:
(Solder wettability test)
a glossy surface of a copper foil with a thickness of 12 μm is coated with the chelating flux agent, and a solder ball with a diameter of 0.5 mm is placed on the chelating flux agent; the resultant is then heated for 1 minute on a hot plate kept at 235° C. to melt the solder, which is then cooled at room temperature; and after the cooling, a radius (a) of the solder ball spread on the copper foil and a height (b) of the solder ball were measured, and a contact angle was calculated according to the following expression:

contact angle of solder ball=2 arctan{(b)/(a)}.