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Advanced Wafer Dicing of Ultra Thin, Low-Potassium Die Using Reactive Ion Etching Plasma Technology

IP.com Disclosure Number: IPCOM000146444D
Publication Date: 2007-Feb-13
Document File: 3 page(s) / 118K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a new method for wafer dicing, using a reactive ion etching (RIE) plasma process to etch the scribe line of the wafer. Benefits include eliminating die cracking, increasing wafer density, and improving processing times.

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Advanced Wafer Dicing of Ultra Thin, Low-Potassium Die Using Reactive Ion Etching Plasma Technology

Disclosed is a new method for wafer dicing, using a reactive ion etching (RIE) plasma process to etch the scribe line of the wafer. Benefits include eliminating die cracking, increasing wafer density, and improving processing times.

Background

The current state of the art uses a composite rotating blade with diamond grits to cut wafers into individual die. However, due to the demand for silicon stacking for thin packages and multi-functional die, there is a need to thin the die to <3 mils. The thinner the die, the higher the risk of die cracking, especially when a mechanical method is used. Thin wafers (1~2mils) will shatter/break into pieces when the composite rotating blade is used. Also, interlayer dielectric (ILD) cracking occurs because the low-potassium wafer is very brittle, making it impossible to use the saw to dice wafers.

Currently, there is no method to dice thin wafers to a <3 mils wafer thickness. The existing mechanical sawing is limited only to wafer >3 mils thickness (see Figure 1). Die cracking for the >3 mil die is solved by optimizing the blade and saw equipment parameters. The blade grit size, as well as the saw blade feed rate and rpm, are optimized to reduce the die breakage. The low-potassium wafer ILD cracking is currently solved by using a combined laser and sawing process. (see Figure 2). The laser grooves the street to remove the ILDs and expose the base silicon material . After the ILDs have been removed, the wafer saw blade cuts through the wafer. However, the process is very slow and very expensive.

General Description

The disclosed met...