US 7,063,524 B2 · Apparatus for increased dimensional accuracy of 3-D object creation

Abstract

A stereolithographic (STL) apparatus for forming structures such as semiconductor die packages is described which uses a laser beam focused to a generally annular “spot” having an annulus of enhanced laser power surrounding a central “hole” of reduced (or no) laser power. The structures are formed of a stack of light-polymerized photopolymer layers. Scanning of a beam having power concentrated in the annulus enables simultaneous production of a self-supporting structure having at least semisolid, smooth lateral outer polymer walls and an upper hardened polymer skin extending over liquid polymer still lying between the walls. The structure may be subjected to heat or broad source light of suitable wavelength after removal from the STL apparatus to accelerate complete polymerization of the structure to a solid state.

Claims26

Dependent claims

An apparatus for fabricating a three-dimensional solid object from a liquid photopolymer, the apparatus comprising:

a reservoir for containing the liquid photopolymer;
a vertically movable support disposable within the reservoir at least to a depth wherein a layer of the liquid photopolymer contained by the reservoir lies above the support;
a laser light generator assembly configured to produce light of at least one wavelength suitable for initiating polymerization of the liquid photopolymer in the form of a laser beam directable to a position adjacent the support and focused to a spot consisting essentially of a generally annular cross-sectional shape having an outer, annular portion exhibiting a power density and an inner, substantially circular central portion surrounded by the outer, annular portion and exhibiting, across a diameter thereof, a power density of less than about 0.6 times the power density of the outer, annular portion;
and
a device configured to initiate and control scanning of the spot adjacent the support.

2 more elements

Dependencies are inferred from the claim text.

Apparatus for increased dimensional accuracy of 3-D object creation

Life of this patent

Apparatus for increased dimensional accuracy of 3-D object creation

Life of this patent

Abstract

Claims26