Development of Dicing Die Attach Film (DDAF) for Small Dies

Abstract

In recent years, the demand for ever smaller dies including Micro Electro-Mechanical System (MEMS) and sensors is dramatically increasing. Technologies such as automated driving technology are taking off and market pressures to reduce package size and increase the performance in mobile devices are increasing. DDAF increasingly is being utilized in these applications to bond dies to substrates and other dies. DDAF can be used both in the dicing and the die bonding process replacing the need for two separate materials to dice and bond dies. It is composed of DAF (Die Attach Film) and base material, and the DAF layer is what bonds small dies to substrates and other dies. Conventional DDAF however is susceptible to Transfer Failure (TF) with smaller die sizes. It is a failure mode in which the DAF layer peels off from the backside of the die during the die picking up (PU) process. There are multiple root causes for this issue; small dies have small DAF attachment area and smooth die backsides for increased die strength results in an inability of the DAF to anchor itself to the die. However, package reliability was decreased due to the material’s inability to embed itself on to the substrate. Effect factors for suppression of TF with high substrate embedding were explored. To explore these factors a right-angle tear strength method was implemented. Upon analysis of the data a new parameter for the suppression of TF was discovered. This parameter showed a strong correlation to TF. A new DDAF was developed that mitigates TF during PU proess.