Rotary chip attach process
View Patent ↗A rotary chip attach process and manufacturing approach takes chips (e.g., integrated circuits (ICs)) from a wafer in a rotary process. A chip wafer with a positioning unit is placed over the top of a sprocketed wheel that picks the ICs directly from the wafer and moves them in a semi-continuous in-step motion to a web that will accept the ICs. The sprocketed wheel includes chips that are preferably the same type as used in a typical pick-and-place robotic system, with vacuum heads adapted to pierce the wafer flat membrane (if needed), grab and IC and place and IC as desired. This positioning system keeps the IC's placement in an accurate position on the web, which can be made to move continuously with a plurality of sprocketed wheel placement units in place.
1. A method for transferring integrated circuits to a substrate moving in a first direction, the method comprising:
(a) continuously rotating a rotary unit in-step and in a first rotational direction between a wafer bed and the substrate, the wafer bed including a membrane that supports the integrated circuits;
(b) selecting one of the integrated circuits;
(c) aligning the selected integrated circuit with the rotary unit having pickup members externally placed about the rotary unit;
(d) piercing the membrane of the wafer bed adjacent the supported selected integrated circuit with one of the pickup members;
(e) taking the selected integrated circuit from the wafer bed with the one of the pickup members through the membrane;
(f) moving the selected integrated circuit about the rotating rotary unit in-step to the moving substrate; and
(g) placing the selected integrated circuit on the substrate moving in the first direction.
2. The method of claim 1 , further comprising mapping the integrated circuits on the wafer bed as one of desired integrated circuits and unwanted integrated circuits, and wherein-step (b) includes selecting one of the desired integrated circuits only.
3. The method of claim 1 , further comprising continuously moving the substrate in the first direction while the selected integrated circuit is placed on the substrate.
4. The method of claim 1 , further comprising selecting a second one of the integrated circuits, aligning the second selected integrated circuit with the rotary unit, taking the second selected integrated circuit from the wafer bed with a second one of the pickup members, and placing the second selected integrated circuit on the substrate adjacent the placed selected integrated circuit.
5. The method of claim 1 , wherein step (a) includes rotating the rotary unit in-step between the wafer bed and the substrate.
6. The method of claim 1 , further comprising:
before step (d), shifting the wafer bed towards the rotary unit, and
after step (e), shifting the wafer bed away from the rotary unit.
7. The method of claim 1 , further comprising:
before step (d), shifting the rotary unit towards the wafer bed, and
after step (e), shifting the rotary unit away from the wafer bed.
8. The method of claim 1 , the wafer bed being a first wafer bed, and further comprising:
continuously rotating a second rotary unit in-step between a second wafer bed and the substrate, the second wafer bed including a membrane that supports the integrated circuits;
selecting an integrated circuit from the second wafer bed;
aligning the selected integrated circuit from the second wafer bed with the second rotary unit having pickup members externally placed about the second rotary unit;
taking the selected integrated circuit from the second wafer bed with one of the pickup members from the second rotary unit by piercing the membrane of the second wafer bed adjacent the selected integrated circuit of the second wafer bed with the pickup members and grabbing the selected integrated circuit;
moving the selected integrated circuit from the second wafer bed about the second rotary unit to the moving substrate; and
placing the selected integrated circuit from the second wafer bed on the substrate adjacent and in alignment with the selected integrated circuit from the first wafer bed.
9. The method of claim 8 , further comprising continuously moving the substrate in the first direction while the selected integrated circuits are placed on the substrate.
10. The method of claim 8 , further comprising alternatively placing desired integrated circuits from the first wafer bed and the second wafer bed on the moving substrate.
11. The method of claim 1 , wherein step (a) further comprises rotating the rotary unit unidirectionally.