Gerald Kreindl

3D Die-to-wafer Cu/Sn Microconnects Formed Simultaneously with an Adhesive Dielectric Bond Using Thermal Compression Bonding

The simultaneous formation of Cu/Sn microconnects and an adhesive bond during wafer level thermal compression bonding was evaluated using a 3D enabled single metal level test die and wafer. The wafer level bond process relied on locally dispensed adhesive to fix the dice to the wafer prior to bonding and to become a permanent bond during the bonding process. The die-to-wafer microconnect resistance was measured for micropad pitches of 59, 64, and 69 ¿m. The robustness of the Cu/Sn and adhesive bond was demonstrated by thinning the bonded die to 50 ¿m. Package level reliability testing of parts that were wire bonded into a thermally enhanced plastic ball grid array (PBGA) package indicates good reliability behavior and the absence of any intrinsic reliability-related issues in the microconnects.

CMOS image sensor wafer-level packaging

This article presents the advances in wafer-level processing and integration techniques for CMOS image sensor module manufacturing. CMOS image sensors gave birth to the low-cost, high-volume camera phone market and are being adopted for various high-end applications. The backside illumination technique has significant advantages over the front-side illumination due to separation of the optical path from the metal interconnects. Wafer bonding plays a key role in manufacturing backside illuminated sensors. The cost-effective integration of miniaturized cameras in various handheld devices becomes realized through the introduction of CMOS image sensor modules or camera modules manufactured with wafer-level processing and integration techniques. We developed various technologies enabling wafer-level processing and integration, such as (a) wafer-to-wafer permanent bonding with oxide or polymer layers for manufacturing backside illuminated sensor wafers, (b) wafer-level lens molding and stacking based on UV imprint lithography for making wafer-level optics, (c) conformal coating of various photoresists within high aspect ratio through-silicon vias, and (d) advanced backside lithography for various metallization processes in wafer-level packaging. Those techniques pave the way to the future growth of the digital imaging industry by improving the electrical and optical aspects of devices as well as the module manufacturability.

Nanoimprint lithography for microfluidics manufacturing

The history of imprint technology as lithography method for pattern replication can be traced back to 1970’s but the most significant progress has been made by the research group of S. Chou in the 1990’s. Since then, it has become a popular technique with a rapidly growing interest from both research and industrial sides and a variety of new approaches have been proposed along the mainstream scientific advances. Nanoimprint lithography (NIL) is a novel method for the fabrication of micro/nanometer scale patterns with low cost, high throughput and high resolution. Unlike traditional optical lithographic approaches, which create pattern through the use of photons or electrons to modify the chemical and physical properties of the resist, NIL relies on direct mechanical deformation of the resist and can therefore achieve resolutions beyond the limitations set by light diffraction or beam scattering that are encountered in conventional lithographic techniques. The ability to fabricate structures from the micro- to the nanoscale with high precision in a wide variety of materials is of crucial importance to the advancement of micro- and nanotechnology and the biotech- sciences as a whole and will be discussed in this paper. Nanoimprinting can not only create resist patterns, as in lithography, but can also imprint functional device structures in various polymers, which can lead to a wide range of applications in electronics, photonics, data storage, and biotechnology.

Low temperature packaging of BioMEMS and Lab-on-chip devices

BioMEMS in general and specifically Lab-on-chip devices for point-of-care diagnostics offer tremendous potential to improve the health care situation in developed and developing countries. Lab-on-chip devices enable the widespread and fast detection of infectious diseases as well as the continuous diagnosis and customized treatment of chronic diseases like diabetes. Implementing microfluidics and micromanufacturing enables massive parallelization of the diagnosis thereby allowing multiple different tests at once.

Nanoimprint activities in Austria in the research project cluster NILaustria

The NILaustria research project cluster consists of 8 individual research projects and aims to improve nanoimprint lithography in an application driven approach. The cluster is presented as well as highlights from the projects, e.g. the replication of 12.5nm half pitch features using working stamp copies, topics from organic electronics, metamaterials and SiGe technology. An outlook on the new activities is given.