Method and apparatus for mounting semiconductor chips

An apparatus for mounting a semiconductor chip onto a substrate having a portion of adhesive, the apparatus comprising a bondhead with a pick-up tool, wherein the pick-up tool is freely movable in a vertical direction between an upper limit position and a lower limit position and wherein the bondhead contains a chamber to which compressed air and/or vacuum can be applied and in which an upper end of the pick-up tool runs on air-tight bearings, wherein the chamber is connected to a pressure chamber the volume of which is at least ten times larger than the volume of the chamber, the apparatus adapted to:

• present a substrate having a portion of adhesive on a support;
• move the bondhead carrying the semiconductor chip to a position over the substrate;
• fix the pickup tool in the upper limit position by means of vacuum;
• lower the bondhead to a predetermined height above the support;
• release the fixing of the pick-up tool so that the pick-up tool falls downwards towards the adhesive and presses the semiconductor chip onto the adhesive while the bondhead remains at said height;
• control a falling speed of the pick-up tool by controlling a strength of the vacuum in the chamber in accordance with a given time profile;
• and
• raise and move away of the bondhead at a predetermined time after releasing the fixing of the pick-up tool.