No abstract

One of the most challenging tasks in pre-assembly, coming up in recent years, is to produce thin chips. Lots of applications are standing on the horizon: Smart-cards (creditcard, telefon, security), tags and labels (tube-tickets, pricelabels), memory applications (stacks of thin memory-chips). Power-and high-frequency devices are also getting thinner. Several procedures have been suggested and are in some cases already in production for manufacturing thin chips. Most promising are cluster-tools, combining several single processes in one equipment. We will look at the different process-flows and equipment-tools which are available or anounced nowadays.Main aspect in judging these methods are compatibility between Front-End and Back-End, process-stability, quality and cost-effectiveness. According to product needs there will be different processes which are to be considered as best practice. IntroductionThe thickness of logic chips is being reduced year after year. This trend will continue in the near future. Applications like smart-cards, powerchips and high frequency devices long for thinner chips in their final packaging.The main tasks resulting from these changes have to be done in PreAssembly. Receiving thick wafers (6 inch 675 µm, 8 inch 725 µm), pre-assembly has to provide thin chips (200 µm, 100 µm, 50 µm) in a form that can easily be processed by Assembly-Lines. During the process steps of Pre-Assembly the wafers are transferred into separated chips. So preassembly can be recognized as the link between Front-End and Back-End.

No abstract

No abstract

We report on the development of a dry lasersingulation process for Si-wafers with back side metallization targeting small die sizes below 0.07 mm2. The dicing technology aims at improved manufacturing of diodes with thicknesses ranging from approx. 100 µm to 150 µm, die sizes down to 230 x 230 µm2 and metallized back side metallization layers used for solder die attach. We discuss the impact of the laser process on subsequent assembly processes as well as on the die itself. Particular emphasis is set on the laser induced modification of the mechanical properties within the wafer, e. g. the reduction of the die strength. For the wafer technology under evaluation, the laser process is considered to be superior to standard blade dicing approaches