Plasma Dicing of Wafers for Reduced Total Cost of Ownership and Increased Quality

Abstract

It could be argued that the defining feature of the Electronics Industry is the ability to miniaturize. Every person with a passing interest in electronics has heard of Moore’s Law: the processing power of affordable CPUs - or the number of transistors on a chip - will roughly double every two years. It is credit to both Gordon Moore’s foresight, and the technical and engineering teams around the world who continue to innovate, that the ‘Law’ is still even being discussed today. Part of the reason for chip size reduction lies in the shrinking of technology nodes (process geometries). Currently the smallest node that is being manufactured in mass volume is 7nm, and even smaller sizes are under development in the industry. The increase in processing power and speed and the miniaturization and integration of electronic functions that continue to result from such technological advances lie at the heart of the pervasiveness of electronics in our everyday lives: the smart phones that we rely on; the uptake of artificial intelligence in smart homes and cities; driverless vehicles; remote medical home diagnostics - there is not one aspect of life that electronic products and systems have not penetrated. But for this to continue, it is not only in the area of photolithographic processing that technology needs to keep innovating. Once a wafer has been created it must be singulated into individual dies, and as dies are becoming smaller and thinner, many products are facing difficulties caused by the singulation or dicing process. New challenges include: increasing material loss due to the width of the dicing street; mechanical damage such as chipping; and increasing processing time.Panasonic has developed a plasma dicing process which addresses these issues and in certain circumstances can replace mechanical dicing. Advantages of plasma dicing are:i.Damage-free / Chipping-free processii.Increased chip yield per waferiii.Water-free processiv.Flexible chip shapev.Fast etching speedvi.Total Dicing Process FlowThe throughput of a plasma chamber depends mainly on wafer thickness and wafer material, and is quite independent from wafer size or chip size. By using plasma dicing, the throughput can be more than 4 or 5 wafers per hour. Such throughput cannot be achieved by any line-by-line dicing method when small chips are required. Significant cost savings can be expected.The combination of higher throughput and increased chip yield per wafer lead to an overall reduced total cost of ownership, and the damage-free / chipping-free nature of plasma dicing leads to an increase of chip-strength and overall quality.