Two heads are better than one for flip chip bonder

The PESL DB5-TSV vertical-head ultrasonic flip chip bonder can be rapidly converted to horizontal ultrasonics and can be used as a highly accurate pick and place machine.

The PESL DB5-TSV vertical-head ultrasonic flip chip bonder can be rapidly converted to horizontal ultrasonics and can be used as a highly accurate pick and place machine.

The vertical ultrasonic head enables improved planar attachment of very fragile chips such as gallium arsenide and for some of the very small microwave chips presently in development.

Conventional gold bump chips can then be bonded using either horizontal or vertical ultrasonics, involving only a very quick and simple change of the active head unit.

Without either ultrasonic head the DB5 is a very accurate flip chip pick and place machine for normal reflow, or for pick, epoxy, place and reflow.

In vertical ultrasonic format the PESL DB5-TSV unit offers accuracy of 2-3um and very low force on the chip.

The unit was developed especially for small chips with gold contacts - generally these have required high force to adequately bond with vibration transmitted across the chip.

However, using a vertical application of the ultrasonic wave, bonding reliability is greatly improved.

This is especially true where planarity problems on large chips can be eliminated; thus generating greatly improved yields.

Planarity refers to the tendency for large chips to tilt, thus leaving some balls off the bond plane and not connecting.

Vertical application of the ultrasonic horn also has advantages in terms of the simplicity of design and operation which in turn lead to the possibility of improved performance where high accurate placement is required in small recessed packages.

The DB5-TSV has an innovative design, which combines a vertically mounted camera and targeting system, together with a high precise mouse driven table.

Ease of use is a key factor in this machine's success, allowing for users with only a minimum of training to effectively use the equipment.

It is constructed using a solid cast aluminium base with mechanical parts designed to conform to good kinematic practice with automatic backlash compensation for high rigidity, stability and independence from environmental conditions.

Features of the new PESL vertical ultrasonic bonder include: digital force settings; dual camera heads; vertical viewing and placement target generation on screen; x-y and theta adjustment; adjustable pick, place and pause; all with manual override.

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