Method and apparatus for assembling a conformal chip carrier to a flip chip

A method for attaching a semiconductor chip to a substrate, the semiconductor chip having an array of joining material bumps, the substrate having an array of conductive pads corresponding to the array of joining material bumps, the method comprising the steps of:

• providing a fixture comprising a body, the body having a first cavity for containing the semiconductor chip and a second cavity in communication with the first cavity for containing the substrate,
• inserting the semiconductor chip into the first cavity in the fixture with the joining material bumps facing upward,
• placing the substrate over the semiconductor chip with the conductive pads opposing and in contact with the joining material bumps, and
• heating the joining material bumps whereby the weight of the substrate acts against the joining material bumps and aids in the attachment of the semiconductor chip to the substrate to form electrical connections therebetween.

A method for attaching a semiconductor chip to a substrate, the semiconductor chip having an array of joining material bumps, the substrate having an array of conductive pads corresponding to the array of joining material bumps, the fixture comprising:

• providing a fixture comprising a first plate having a first opening for disposal of the semiconductor chip therein, a second plate stacked below the first plate and having a thickness substantially equal to the thickness of the substrate, the second plate further having a second opening opposing the first opening for disposal of the substrate therein, and a third plate stacked below the second plate;
• (a) stacking the second plate on top of the third plate;
• (b) inserting the substrate into the second opening with the conductive pads facing upward;
• (c) stacking the first plate on top of the second plate such that the substrate is flattened in the second opening under the weight of the first plate;
• (d) inserting the semiconductor chip into the first opening with the joining material bumps opposing and in contact with the conductive pads;
• and
• (e) heating the joining material bumps thereby attaching the joining material bumps to their corresponding conductive pads during solder reflow to form electrical connections therebetween.