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HSQ Bridge for Magnetic Read Head Definition Disclosure Number: IPCOM000010210D
Original Publication Date: 2002-Nov-05
Included in the Prior Art Database: 2002-Nov-05
Document File: 2 page(s) / 618K

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HSQ Bridge for Magnetic Read Head Definition

This disclosure describes a methodology for building bridge structures made of HSQ (Hydrogen Siles Quioxane) to facilitate metal liftoff. Such a liftoff process is directly applicable to defining very narrow magnetic read heads.

The central idea of this disclosure is to employ HSQ as a dielectric underlayer for image transfer. This approach takes advantage of the strength of HSQ and its process simplicity. The process flow is illustrated in Figure 1. In step 1, a polymer underlayer
(e.g. Durimide, ~50nm thick) is coated on a wafer. This is followed by spin-coating of HSQ (~150nm thick). Curing of HSQ is performed conventionally at temperatures above 300C to densify HSQ. However, to preserve read sensor integrity, the processing temperatures must be kept below 200C typically. To overcome this heating issue, we cure the HSQ layer with electron-beam. This is performed at low energy (10kV) because the required dose for curing is lower. Lower dose implies lower heating. Convention lithography is performed next (steps 2 and 3), and the resist image transferred into the HSQ and the polymer underlayers by reactive-ion etching (step 4). In step 6, a HSQ bridge is formed through an isotropic ashing step. An SEM micrograph of such a bridge is shown in Figure 2.

In summary, the main advantages of the HSQ bridge approach disclosed here are:

Extendability; compared to current POR since this approach is not limited by the