One of the newest additions to the EMPF is the Bondjet BJ820 thin wire bonding machine from Hesse & Knipps (Figure 5-1). The BJ820 is very capable of handling all challenging aluminum or gold wire and ribbon bonding applications on a single platform - RF and microwave device, COB (chip on board), MCM (multi-chip modules) and hybrids, fiberoptics and automotive requirements.

The BJ820 features high repeatability of 1μm at a balanced encoder resolution of 20nm.  The BJ820 bonds all technically possible fine pitch applications, its greatest advantage being increased process stability which results from this high repeatability rate. This rate enables reliable bonding of extremely small bond pads with a larger wire diameter. 

Another outstanding feature is the extra large working area of 305 mm x 410 mm, which allows the processing of extra large products. This area can be split into two or more smaller areas for processing smaller products or substrates. Independent loading and unloading of the individual work areas during operation enables the machine to run continually with no idle time for indexer activity. This elimination of indexing further increases productivity. A wide range of solutions are available from clamping and automation to boards, packages, ceramics, lead frames, boat or carrier applications, in addition to applications which require adjustable rail width, shuttle or tilt operations.  Complex projects include chip-on-glass (COG) applications, where 305 mm x 305 mm glass boards are bonded in high volume without indexing. Other projects involve bonding 3D-packages that are automatically rotated or tilted between the individual steps.

The BJ820 has many advanced features. Depending on the application, 5 to 6 wires are processed per second. In volume COG applications, about 5 wires per second are bonded with a length of 2 mm.  The BJ820 also manages an enormous amount of process data for each individual bond. Without loss of productivity, the wire deformation is recorded as a function of time for each welding process with a resolution of 25 nm. Simultaneously, the bonder calculates the progression of the admittance, which can be used in connection with the deformation curve as a quality characteristic.

To evaluate the bond quality, target profiles can be defined for the time progression of wire deformation and transducer current. After the welding process is finished, the measured progression of each wire can be compared to these profiles. Typical errors, such as insufficient substrate clamping, damaged bond pads or wire loss due to contamination can be recognized.

The BJ820 assures precise welding parameters so that uniform bonds are created by applying constant conditions, and any disturbing factor or anomalies can be recognized. The analysis of the deformation and transducer current curves enables the process expert to define preset process parameters and control their consistency.  High precision and controllable force increase the reproducibility of bonds, simplify the optimization of narrow parameter windows in difficult applications and help prevent cratering on sensitive chips, in addition to reducing cycle time.

Despite its large working area, the BONDJET BJ820 has a relatively small footprint and is integration-friendly. With a footprint of only 720 x 1250 mm, it fits easily into in-line plans or concepts. The integrated soft-PLC, the standard SMEMA input and outputs as well as the large conveyor gate in SMEMA height simplify integration.

The Bondjet BJ820 is a valuable alternative to ball bonding and other processes, offering very high repeatability for high volume production environments as well as a large control work area for diverse applications.  For more information related to this article, or to schedule a demonstration of the Bondjet BJ820 located at the EMPF, contact Ken Friedman, 610-362-1200 x 279 or via email at kfriedman@aciusa.org.