| abstract |
[Problem] Provided is a solder bump having a desired thickness of a solder bump formed on a mounting substrate such as a printed circuit board having a fine copper electrode without causing problems such as copper corrosion. method. [Solution] There is a case where the prepared substrate (1) and the prepared mask (5) are overlapped, and the molten solder jet is sprayed and placed at the opening of the mask (5). The molten solder (11a) is deposited until it becomes thicker than the thickness of the mask (5), and the molten solder (11a) exceeding the thickness of the mask (5) is removed to form a solder bump of a specific thickness (11) And the process of removing the mask (5), the molten solder (11a) is made of tin as a main component, and contains at least nickel as an accessory component, and further contains silver, copper, bismuth, or the like. Melting the lead-free solder, removing the molten solder (11a) exceeding the thickness of the mask (5), by cutting the edge or an air knife, or by using an organic fatty acid having a carbon number (12-20) The solution (18) is sprayed to solve the above problems. |