Application of underfill via centrifugal force
Embodiments described herein are directed towards enhanced systems and methods for applying underfill (UF) material to fill a gap between electrically coupled semiconductor devices in an integrated device. In some embodiments, uncured UF material may be applied to one edge of the gap, and capillary flow may be employed to distribute the uncured UF material into a first portion of the gap. To fill a second portion of the gap, accelerated motion may be employed. For example, the integrated device may be affixed to a centrifuge, and the centrifuge can be used to spin the integrated device to spread the uncured UF material further into the gap. In some embodiments, the accelerated motion may be employed to distribute the uncured UF material substantially uniformly within the gap. Once the uncured UF material has been spread out, one or more curing processes may be employed to cure the sandwiched UF material.
1. A method for applying uncured underfill (UF) material to a semiconductor device, the method comprising:
forming an electrical bond, via a first laser beam, between the semiconductor device and a target substrate;
applying the uncured UF material to a first portion of the semiconductor device, wherein the first portion of the semiconductor device is proximate to a gap in the semiconductor device;
employing an accelerated motion of the semiconductor device to distribute the applied uncured UF material across a second portion of the semiconductor device, wherein the second portion of the semiconductor device includes the gap in the semiconductor device; and
irradiating a third portion of the semiconductor device with a second laser beam different from the first laser beam that formed the electrical bond, wherein the second laser beam is scanned in a one-dimensional or two-dimensional scanning pattern, after the electrical bond formation and the uncured UF material application, to cure the distributed uncured UF material, and wherein the third portion of the semiconductor device includes a surface of the semiconductor device that is substantially parallel to the gap in the semiconductor device.
2. The method of claim 1 , wherein the semiconductor device is an integrated device that includes a first semiconductor device, a second semiconductor device electrically bonded to the first semiconductor device, and the gap in the semiconductor device is a gap between the first semiconductor device and the second semiconductor device, wherein applying the uncured UF material to the first portion of the semiconductor device comprises dispensing the uncured UF material at an edge of the gap of the semiconductor device.
3. The method of claim 2 , further comprising;
employing a capillary action to distribute the uncured UF material from the edge of the gap into a first portion of the gap; and
employing the accelerated motion of the semiconductor device to distribute the uncured UF material into a second portion of the gap.
4. The method of claim 1 , wherein the accelerated motion of the semiconductor device is a rotational motion of the semiconductor device.
5. The method of claim 4 , wherein a radius of the rotational motion of the semiconductor device is between 2 and 10 centimeters and a rotational frequency of the rotational motion is between 1000 revolutions per minute (RPM) and 12000 RPM.
6. The method of claim 1 , further comprising employing a centrifuge device to generate the accelerated motion of the semiconductor device, wherein the accelerated motion is centrifugal motion, and wherein the distributed uncured UF material includes a nanoparticle gradient distribution along an axis of the centrifugal motion.
7. The method of claim 1 , wherein an acceleration of the accelerated motion of the semiconductor device is between 500 and 5000 meters per second squared.
8. The method of claim 1 , further comprising employing a laser device to generate the laser beam to cure the distributed uncured UF material.
9. The method of claim 1 , wherein the semiconductor device includes a plurality of light-emitting diodes (LEDs).
10. The method of claim 1 , further comprising packaging the semiconductor device into a display device of a head-mounted device comprising a virtual-reality device, an augmented-reality device, or a mixed-reality device.