Underfill contacting stacking balls package fabrication method and structure
View Patent ↗Stacking balls are formed on ball terminals prior to application of an underfill under a flip chip mounted electronic component. The underfill is then applied and directly contacts and at least partially encloses an inner row of the stacking balls closest to and directly adjacent the flip chip mounted electronic component. By forming the stacking balls prior to the application of the underfill, contamination of the ball terminals by the underfill is avoided. This allows the spacing between the ball terminals and the electronic component to be minimized.
1. An electronic component package comprising:
a substrate core comprising a first surface;
first traces coupled to the first surface of the substrate core, the first traces comprising flip chip terminals and ball terminals;
metallic studs coupled to the flip chip terminals;
stacking balls coupled to the ball terminals, wherein the metallic studs have a higher melting temperature than the stacking balls;
an electronic component coupled to the metallic studs; and
an underfill between the electronic component and the first surface of the substrate core, the underfill directly contacting at least some of the stacking balls.
2. The electronic component package of claim 1 wherein the metallic studs comprise copper.
3. The electronic component package of claim 2 wherein the stacking balls comprise solder.
4. The electronic component package of claim 1 wherein the electronic component comprises an active surface comprising bond pads thereon, the electronic component package further comprising:
metallic stud interconnects coupling the bond pads to the metallic studs.
5. The electronic component package of claim 4 wherein the underfill encloses the metallic studs and the metallic stud interconnects.
6. The electronic component package of claim 1 wherein the underfill directly contacts a lower stacking ball portion of a first stacking ball of the stacking balls, an upper stacking ball portion of the first stacking ball being exposed from the underfill.
7. The electronic component package of claim 6 wherein the underfill does not contact a second stacking ball of the stacking balls.
8. The electronic component package of claim 1 wherein the underfill tapers to become thinner as a lateral distance from the electronic component increases.
9. The electronic component package of claim 1 further comprising:
a package body enclosing the electronic component and the underfill; and
via apertures extending in the package body to expose the stacking balls.
10. An electronic component package comprising:
a substrate core comprising a first surface;
first traces coupled to the first surface of the substrate core, the first traces comprising a ball terminal and a flip chip terminal;
a metallic stud coupled to the flip chip terminal;
a first stacking ball coupled to the ball terminal, wherein the metallic stud has a higher melting temperature than the stacking ball;
an underfill directly contacting the first stacking ball;
a package body enclosing the underfill; and
a first via aperture extending entirely through the package body and partially into the underfill, the first via aperture exposing the first stacking ball.
11. The electronic component package of claim 10 wherein the package body comprises a principal surface, the first via aperture extending from the principal surface to the first stacking ball.
12. The electronic component package of claim 10 further comprising:
a second stacking ball; and
a second via aperture formed entirely within the package body, the second via aperture exposing the second stacking ball.
13. The electronic component package of claim 12 wherein the underfill does not contact the second stacking ball.
14. An electronic component package comprising:
a substrate core comprising a first surface;
first traces coupled to the first surface of the substrate core, the first traces comprising flip chip terminals and ball terminals;
stacking balls coupled to the ball terminals;
an electronic component coupled to the flip chip terminals by metallic studs, wherein the metallic studs have a higher melting temperature than the stacking balls; and
an underfill between the electronic component and the first surface of the substrate core, the underfill directly contacting an inner row of the stacking balls, wherein the underfill does not contact an outer row of the stacking balls, the outer row of the stacking balls being located at a greater lateral distance from the electronic component than the inner row of stacking balls.
15. The electronic component package of claim 14 wherein the underfill tapers to become thinner as a lateral distance from the electronic component increases.
16. The electronic component package of claim 14 further comprising:
a package body enclosing the underfill; and
a first via aperture extending entirely through the package body and partially into the underfill, the first via aperture exposing a stacking ball of the inner row of stacking balls.
17. The electronic component package of claim 16 further comprising:
a second via aperture formed entirely within the package body, the second via aperture exposing a stacking ball of the outer row of stacking balls.
18. The electronic component package of claim 14 wherein the underfill directly contacts lower stacking ball portions of the inner row of stacking balls, upper stacking ball portions of the inner row of stacking balls being exposed from the underfill.