LED printhead arrays technology, laser or ink jet, utilizes arrays of lasers or ink jets on individual die. The lithography processes used to create the arrays on each die are more than adequate to produce high quality images. Print heads typically use high aspect ratio die to maximize the number of pixels per die and to minimize the amount of silicon.
Palomar Technologies Solution
Palomar Technologies research shows that control of adhesive is a critical step required for ultra high-accuracy placement of die. High-automated ball bonding strings together LED arrays with excellent looping.Those arrays requiring greater accuracy and eutectic die attach included active optical cables and P-Side down lasers. Epoxy applications, in addition to the above-named, are 3D MEMS stacking and laser marker heads.
The technical paper "Micron Level Placement Accuracy for High Aspect Ratio Die in Printing Products" details micron-level accuracy of 1-5 micron for large die with lengths greater than 30mm and high aspect rations for 10:1.
Both side-by-side and end-to-end die arrays are discussed with their corresponding results. Also discussed are fine line dispensing and input prior to die bonding; material feeding, ID tracking, and vibration isolation relating to ultra fine placement accuracy are covered as well.