Patent landscape and market segments of sintered silver as die attach materials in microelectronic packaging

Abstract

Sintered silver (Ag) is a porous silver attaching the semiconductor die to the microelectronic substrates. The market sizes for sintered Ag are explored, and the relevant patents are analyzed at macro and micro-levels. At the macro-level, patenting activity moves to Stage 2 of the technology life-cycle “s-curve”. In stage 2, patenting slows down before the next surge in patenting, likely to be spurred by the wider adoption of wide band-gap semiconductor. The low profitability of sintered Ag also coincides with the available market research reports on the three major market of this technology, i.e., power module, power discrete technology and consumer integrated circuits. However, the patent owners are not abandoning their patents applications. Only eleven entities are co-filing patents related to sintered Ag based on 350 patents and patent applications analyzed here. Such trend suggests the nascent characteristics and continuing investment in this technology. At the micro-level, patenting addresses the following issues. Firstly, pressure assisted sintering is necessary and more reliable than pressureless sintering but the former requires additional process controls and capital investments than the latter. The current state of the art of sintered Ag joint also favours sintering in an ambient environment that oxidizes the substrate. This oxidation poses a delamination risk, and a reliability concern to the microelectronic packages. Lastly, sintered Ag paste favours sintering on the Ag or Au-metallized substrate that represents an additional cost to the customers.