Method and apparatus for connecting connection elements to the substrate of a power semiconductor module by welding

Apparatus for connecting a connection element having a contact foot to a conductor track of a substrate, the conductor track having a contact point, the connection between the connection element and the substrate being established by welding, wherein the apparatus comprises:

• a bottom element;
• an abutment for positioning said bottom element, said abutment including:
• a first partial abutment having a metal shaped body with a modulus of elasticity of between about 50 and about 300 kN/mm2;
• and
• a second partial abutment having an elastic shaped body with a modulus of elasticity of between about 10 and about 500 N/mm2, and wherein said bottom element rests on said second partial abutment;
• a holding device for fixing said bottom element on said abutment;
• a positioning device for positioning the connection element in relation to the substrate so that the contact foot rests on the contact point;
• and
• a sonotrode for connecting the contact foot to the contact point.