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Technical Insight

Magazine Feature
This article was originally featured in the edition:
2022 Issue 4

New Brewer Science bonding & dielectric materials deliver packaging solutions for 5G, IoT devices


Semiconductor IC packaging techniques include the utilization of 3D integration to increase chip density, maximize performance and reduce power consumption. Brewer Science, a global technology leader in the development and manufacturing of innovative materials and processes, has introduced its latest packaging solutions utilizing a permanent bonding material and a photo-imageable dielectric for the fabrication of cutting-edge semiconductors as well
as 5G and IoT microelectronic devices.

By Baron Huang, Mei Dong, and Ziwei Liu, Brewer Science

Permanent Bonding Material with High Thermal Budget
Bonding two
components together permanently is applied in many fields of advanced packaging to offer a z-axis direction of integration for the fabrication of three-dimensional integrated circuits (3D ICs). Such permanent bonding techniques include direct/fusion bonding, anodic bonding, soldering, and thermocompression. While fusion bonding is still the most frequently used permanent bonding technology in today’s semiconductor industry, there is a fast-growing trend for adhesive bonding.

Adhesive bonding, which develops a bond connecting one surface to another using a polymeric material as the intermediate layer, brings significant advantages including: 1) improved design flexibility; 2) good surface planarization and adaptability to surface topography; 3) lower bonding temperature for protecting sensitive components; and 4) better tolerance to particles. With all these merits, adhesive bonding has recently received much attention for microelectromechanical systems (MEMS) packaging and heterogeneous integration to assemble individual IC components such as logic chips, memory chips, and image sensor devices together into high-density, ultra-thin integrated packages. Such modules are needed for high-performance computing applications such as artificial intelligence (AI), data centers, 5G, and high-end mobile products.

Brewer Science previously introduced its first permanent bonding adhesive, the PermaSOL® family of materials, at the European 3D & Systems Summit. PermaSOL materials were designed to address chip-level and wafer-level packaging requirements by providing reliable bonds with good thermal stability and with low moisture absorption. Brewer Science is now introducing its next generation of permanent bonding materials (PBM) with excellent thermal stability and an improved thermal budget up to 350°C. These materials further provide room temperature bonding with low pressure, low dielectric constant, high chemical resistance, and long shelf life.

In comparison to benzocyclobutene, a widely used bonding adhesive, the Brewer Science next generation PBM exhibits even lower curing temperature, smaller tensile strength and modulus, and larger CTE. These characteristics make the Brewer Science material a ‘super low-stress resin’ providing the benefits of low warpage, which brings up promising opportunities for applications on flexible substrates.

Next generation PBM exhibits good thermal stability with a decomposition temperature above 470°C in a nitrogen atmosphere. The bonding can be achieved at 25°C, 2 kN, for 2 minutes, due to the intrinsic flexibility and fluidity of the material.