Method of fabricating paste bump for printed circuit board

A method of fabricating a paste bump for a printed circuit board, comprising:

• preparing a base plate;
• printing a conductive paste on the base plate and drying the conductive paste on the base plate, thus forming a first paste bump;
• flattening an upper surface of the first paste bump through coining;
• and
• printing a conductive paste on the first paste bump and drying the conductive paste on the first bump, thus forming a second paste bump which has a height lower than or equal to that of the first paste bump,
• wherein the printing a conductive paste on the base plate and drying the conductive paste on the base plate comprises
• placing a first mask having a hole having a first size on the base plate;
• applying a conductive paste on the first mask, and pressing the conductive paste using a squeegee;
• filling the hole having a first size in the first mask with the conductive paste, and sticking a bottom of the conductive paste to the base plate;
• and
• removing the first mask and drying the conductive paste, thus forming the first paste bump.

A method of fabricating a paste bump for a printed circuit board, comprising:

• preparing a base plate;
• printing a conductive paste on the base plate and drying the conductive paste on the base plate, thus forming a first paste bump;
• flattening an upper surface of the first paste bump through coining;
• and
• printing a conductive paste on the first paste bump and drying the conductive paste on the first bump, thus forming a second paste bump,
• wherein the printing a conductive paste on the first paste bump and drying the conductive paste on the first bump comprises
• placing a second mask having a hole having a second size which has a size smaller than or equal to the hole in the first mask on the first paste bump;
• applying a conductive paste on the second mask, and pressing the conductive paste using a squeegee;
• filling the hole having a second size in the second mask with the conductive paste, and sticking a bottom of the conductive paste to an upper surface of the first paste bump;
• and
• removing the second mask, and drying the conductive paste, thus forming the second paste bump,
• wherein the second mask has a height lower than or equal to that of the first mask.