With the well-respected die attach brands of Hysol® and Ablestik®, Henkel has long been recognized for consistently pushing the bar higher when it comes to advanced semiconductor materials development. This pioneering philosophy has led to the development of yet another groundbreaking materials advance and the launch of Henkel’s Ablestik 8000™ Wafer Backside Coating™ (WBC) technology.

Utilizing the proven materials deposition techniques of stencil printing, screen printing and spin coating, Henkel’s WBC solution allows packaging specialists to efficiently coat the back of wafers with die attach materials down to 20 microns in thickness. Unlike conventional dispensing methods where throughput is limited and set-up time for certain products can be time-intensive, printing or spin coating materials onto the wafer delivers a tightly controlled, high UPH and cost-effective solution for high-volume die attach adhesive deposition. The WBC solution also allows for bondline thickness control to customer specifications, maximization of the chip footprint through the elimination of the fillet and repeatable material uniformity to ensure no die tilt.

“This latest product from Henkel is but one more example of what ingenuity and cooperative partnership can achieve,” says Dr. Michael Todd, Henkel Vice-President of Product Development and Engineering. “Our materials scientists, working in close cooperation with mass imaging leader DEK, have developed a robust systems approach to deliver a complete offering that incorporates high-performance, manufacturable materials with a machine platform capable of ultra-precise die attach deposition. Henkel strives to deliver risk-free solutions that enable our customers’ competitiveness through a total process approach and this is, in fact, what the WBC project has achieved.”

The new Ablestik 8000 series materials are available in conductive and non-conductive formulations and have been engineered to address the requirements of smaller die sizes (less than 3mm x 3mm), thus enabling the high throughput production of packages such as COLs and SOs as well as TSOPs and QFNs that generally have tight design tolerances and require controlled flow. While die attach films are also controlled flow materials, the cost of film products can be as much as 20% to 30% higher than that of Henkel’s WBC solution and, therefore, not an option for low-cost manufacturing. Other devices, such as discretes and small power ICs, can also benefit from the efficiencies afforded by Ablesitk’s high-temperature WBC material as a viable and effective alternative to standard solder-based processes.

Cycle times are also greatly enhanced with WBC technology, as the printing process and full coating of the wafer backside can take place in as little as 10 seconds and has successfully achieved coating thicknesses of 20 microns on wafers as thin as 100 microns and up to 300mm in diameter. Once the wafer is coated, the Ablestik WBC material is then B-staged where the material is advanced to a secondary, partially cured film-like, tack-free state, following which the wafer can be stored for later use.

“Current, commercial Ablestik WBC materials are used in production for single die configurations,” says Todd. “However, we are working on some novel application processes and have had success achieving coatings that are less than 10 microns thick. It is certainly conceivable that our WBC technology will quickly become an alternative to film for stacked die applications as well.”

For more information on Henkel’s Ablestik 8000 series Wafer Backside Coating materials or any of the company’s die attach innovations, log onto http://www.ablestik.com/ or call the Irvine, California headquarters at 949-789-2500.