SPREKER

Bas de Kruif, TNO

TITEL

Collocated measurement system for high-accuracy, high-volume die bonding

ABSTRACT

Recent developments in the semiconductor industry (ultra fine pitch dies, 3D integration) indicate that in the near future there will be a need for die bonding machines that are capable of attaining high placement accuracies as well as high production speeds. In this paper, Thomas de Hoog en André Hoostrate present a new, collocated measurement system for die bonding that makes it possible to achieve a comparatively high level of post-bond alignment accuracy (around 2,5 μm at 3 sigma) while still allowing a reasonably high enough production speed (around 1 placement per second).

The distinguishing feature of the new concept is that measurement of substrate and die position is done with the same camera system, which is fixed to the bondhead. This has two main advantages in comparison to conventional pick-and-place systems. First, the use of a single camera system for die and substrate measurement means that position of die and substrate are measured in the same coordinate system. Conventional pick-and-place concepts use separate cameras. The relative position of these cameras is susceptible to thermal drift which limits the attainable accuracy. Second, in conventional systems, the separate camera that is used for die measurement is at a fixed location in the machine. This means that during each cycle an additional move has to be made over this fixed camera. This extra move can be omitted in the new concept, resulting in a considerable gain in cycle time.

A complete measurement system based on the concept was developed and built by TNO. In order to show feasibility of the concept, the system was integrated in an existing flip-chip die bonder. In this paper, the presenters give a general explanation of the concept and the main features of the system. They go in further detail about the actual implementation and show preliminary results on post-bond alignment accuracy.