Low Cost Glass Interposer Development

Abstract

For high density interconnection IC packages of the future, the outlook is for thinner packages with higher routing densities. With that, managing the substrate warpage becomes critical. Traditional organic substrates may face several challenges for high density I/Os with very fine line interconnections. Glass is one of the candidates that can be used in substrate industry. The infrastructure of glass for LCD industry has already been developed for many years. Glass also has several superior properties than other substrate candidates, such as large panel size availability, adjustable CTE, high modulus, low dielectric constant, low dielectric loss and high insulating ability. In this paper, we successfully demonstrate early manufacturing feasibility of glass substrate with 4 build-up layers starting with a thin glass panel of thickness of 200μm in 508mm μ 508mm panel size format and under the IC substrate manufacturing environment. Fabrication and electrical results of a test vehicle are documented. The test vehicle includes daisy chains that are connected with 100μm diameter through glass via (TGV) in a 200μm thick glass. The laser via in via technology was adopted for double side electrical connection. The copper line width/space of 8/8μm was demonstrated. The total thickness of 4 layers test vehicle is about 390μm. The warpage of glass in comparison with an organic substrate (BT) with 200μm core thickness is 3X better. Further work is needed to develop, fine tune and assess the detailed manufacturability and reliability concerns. Based on this work, it is clear that the potential of glass in IC packaging and integration is tremendous in diverse applications for substrate warpage enhancement.

3D including 3DIC and 3D Packaging (POP)

“…Recent work has shown significant progress in the ability to process glass panels > 500 mm in size [15]. An important outcome of this work demonstrated one advantage of using glass in this application.…”

EFFECT OF REPLACEMENT OF CaO BY La₂O₃ ON THE STRUCTURE, THERMAL AND DIELECTRIC PROPERTIES OF ALKALI-FREE ALUMINOBOROSILICATE GLASSES

“…Glass fibre fabrics have superior properties to other substrate materials, such as having a high insulation ability, an adjustable coefficient of thermal expansion (CTE) matching that of the silicon material, a low dielectric constant and loss. Therefore, glass fibre fabrics have become an attractive candidate in the IC substrate industry to replace the intermediate layer materials [2][3][4][5][6]. The glass fibres currently available for electronic printed circuit boards are E-glass fibre, L-glass fibre, S-glass fibre, and T-glass fibre.…”

20″ × 20″ panel size glass substrate manufacturing for 2.5D SiP application

“…Large glass panels are ideally suited for fabrication of interposer where the panel process is expected to provide large number of interposers in each run compared with wafer processing. Additionally, the two sided processing of the panel, the avoidance of CMP processes further enable lower unit cost for the interposer Consequently, glass is an ideal interposer material due to its insulating property, large panel size availability, high modulus and ability to tailor CTE [1][2][3][4][5][6].…”