Layer thickness control for stereolithography utilizing variable liquid elevation and laser focal length
First Claim
1. A method for providing at least an underfilled encapsulant structure for a flip-chip configured semiconductor device having a plurality of external conductive elements projecting from an active surface thereof, the method comprising:
- placing at least one flip-chip configured semiconductor die facing active surface down and above an upper surface of a platform while resting on a plurality of external conductive elements projecting from the active surface;
tilting the platform at an acute angle to the horizontal while raising a surface level of a curable liquid at least above an uppermost edge of the active surface with the at least one semiconductor die in a tilted orientation; and
returning the platform to a horizontal orientation without causing any portion of the active surface to extend above the surface level of the curable liquid.
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Abstract
An apparatus and method for controlling the surface level of a liquid residing within a relatively vertically stationary workpiece support platform disposed within a reservoir for use in stereolithographic processes wherein a layered object or structure is formed by selectively curing portions of the liquid to at least a semisolid state in multiple, at least partially superimposed layers. Providing precise control of liquid depth over the vertically stationary platform as well as focusing of a laser beam for curing the liquid at the varying surface levels thereof relative to the vertically stationary platform is effected using a laser range finder system controlled by a computer used to control the stereolithographic process in a closed loop fashion.
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Citations
6 Claims
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1. A method for providing at least an underfilled encapsulant structure for a flip-chip configured semiconductor device having a plurality of external conductive elements projecting from an active surface thereof, the method comprising:
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placing at least one flip-chip configured semiconductor die facing active surface down and above an upper surface of a platform while resting on a plurality of external conductive elements projecting from the active surface;
tilting the platform at an acute angle to the horizontal while raising a surface level of a curable liquid at least above an uppermost edge of the active surface with the at least one semiconductor die in a tilted orientation; and
returning the platform to a horizontal orientation without causing any portion of the active surface to extend above the surface level of the curable liquid. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification