Paste transfer unit, electronic component mounting device, and transferred film thickness measuring method

A paste transfer unit which is used for transferring a light-transmissible bonding paste to a solder bump in an electronic component mounting device which mounts, on a substrate, an electronic component having a lower surface on which the solder bump is formed, the paste transfer unit comprising:

• a transfer stage to which the bonding paste is supplied and in which at least a part of a transfer area is made of a light-transmitting member, the transfer area being configured to transfer the bonding paste as a result of solder bump moving;
• a squeegee which is arranged above the transfer stage to have a predetermined film-formation-gap from a coating film formation surface on the transfer stage and which moves relatively and horizontally to the transfer stage to thereby form the supplied bonding paste into a coating film with a predetermined film thickness;
• and
• an optical type film thickness measuring sensor which is arranged below the transfer stage and which measures the film thickness of the coating film in the transfer area through the light-transmitting member.