Patent ID: 7658313

Claim:
A ball forming device in a bonding apparatus, said ball forming device comprising: a bonding arm; a capillary attached to one end of said bonding arm; an electronic flame off probe for forming a ball at a tip end of a wire passing through the capillary; and a gas atmosphere forming device for providing in said bonding apparatus to bring a tip end part of the wire into a gas atmosphere, said gas atmosphere forming device including an inner wall element having a plurality of gas ejection ports, a bonding arm side of said inner wall element having an inside open space greater in width than a portion of said bonding arm where said capillary is attached to; an outer wall element secured to said inner wall element with a hollow space section in between; and a gas supply pipe for connecting to said outer wall element to supply a gas into said hollow space section; and wherein said inner wall element is, in lateral cross-section, of a shape selected from a letter U and a letter C; said gas ejection ports provided in said inner wall element are formed so that a volume of gas ejection is greater at an open end side of said inside open space of said shape selected from said letter U and said letter C than at a deep end side thereof; and said gas is one selected from the group consisting of a reducing gas and an inactive gas.