Development of thin package using the glass carrier substrate

Abstract

“The glass carrier substrate” formed on support glass using conventional build-up substrate technologies is developed. This substrate is ultrathin, and is suitable for the applications that thinner packages are highly demanded, such as for mobiles. The advantage of glass as the carrier for the substrate is that the CTE of glass is close to that of silicon. The CTE matching of glass with silicon enables the narrow pitch mounting, because of reduced distortions between the chip and the substrate. When the chip is bonded on the substrate, glass is still combined with the substrate as the carrier. After chip bonding, the substrate can easily peeled off with laser irradiating through glass due to the characters of adhesive layer. To verify the advantage, we prepared the thin substrate and made a connection with a narrow pitch (50um) bump chip, by means of Thermal Compression Bonding with non-conductive paste. The process of injection molding was used for packaging the substrate. We evaluated the reliability of the thin package, by temperature cycle test (JEDEC MSL-3+Cond.B). It was confirmed that the package passed the criteria. It is convinced that the package with glass carrier substrate is an effective solution for making thinner packages.