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A method and apparatus for component to substrate assembly permits in situ reflow of a flip chip (or other suitable component) in a manner which promotes proper settling of the component as solder begins to flow at the contact points between the component and the substrate. The component is heated a

A method and apparatus for component to substrate assembly permits in situ reflow of a flip chip (or other suitable component) in a manner which promotes proper settling of the component as solder begins to flow at the contact points between the component and the substrate. The component is heated and held by a pick-up head while applying downforce that serves to level the component. The initiation of solder reflow can be detected with the pick-up head by sensing a decrease in the downforce. Downforce applied to the component with the pick-up head is then decreased and the retention mechanism holding the component is released, freeing the component from the pick-up head and permitting the component to properly self-center using the liquid solder's surface tension.

대표청구항 ▼

1. A method for in situ assembly of a flip chip semiconductor package to a substrate, comprising: positioning a pick-up head holding the package over the substrate; lowering the package into contact with the substrate; applying a downforce to the package; applying heat to the package; monitor

1. A method for in situ assembly of a flip chip semiconductor package to a substrate, comprising: positioning a pick-up head holding the package over the substrate; lowering the package into contact with the substrate; applying a downforce to the package; applying heat to the package; monitoring the downforce; and removing all downforce when a reduction in downforce is detected. 2. A method in accordance with claim 1, further comprising: displacing the pick-up head a small distance from the package in response to said reduction in downforce. 3. A method in accordance with claim 2, further comprising: continuing to apply heat for a time after said displacing. 4. A method for assembling a semiconductor package to a substrate, comprising: holding the package on a pick-up head of a placement machine; placing the package onto the substrate; applying a downforce to the package; heating the package and the substrate from a heater disposed on the pick-up head; sensing the downforce being applied to the package; and decreasing the applied downward force in response to sensing a decrease in the downforce. 5. A method in accordance with claim 4, further comprising: releasing the package from the pick-up head in response to said decreasing. 6. A method in accordance with claim 5, further comprising: displacing the pick-up head a small distance from the package after said releasing. 7. A method in accordance with claim 6, further comprising: continuing said heating for a time after said displacing. 8. A method for assembly of a component to a substrate, comprising: positioning a pick-up head holding the component over the substrate; lowering the component into contact with the substrate; applying a compressive force between the component and the substrate; performing a bonding process to bond the component to the substrate; monitoring the compressive force; and removing all compressive force when a reduction in compressive force is detected. 9. A method in accordance with claim 8, wherein said performing includes applying heat to the component. 10. A method in accordance with claim 9, further comprising: displacing the pick-up head a small distance from the component in response to said reduction in compressive force. 11. A method in accordance with claim 10, further comprising: continuing to apply heat for a time after said displacing.