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Method for in-place electron bombardment of a low-K ILD or ES film

IP.com Disclosure Number: IPCOM000012783D
Publication Date: 2003-May-28
Document File: 4 page(s) / 114K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for in-place electron bombardment of a low-dielectric constant (low-K) inter-layer dielectric (ILD) or etch-stop (ES) film during the film deposition. Benefits include improved performance.

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Method for in-place electron bombardment of a low-K ILD or ES film

Disclosed is a method for in-place electron bombardment of a low-dielectric constant (low-K) inter-layer dielectric (ILD) or etch-stop (ES) film during the film deposition. Benefits include improved performance.

Background

              The conventional electron bombardment of ILD material, such as some carbon-doped oxides (CDO), after deposition improves the mechanical strength of the film without significantly raising the dielectric constant. The rearrangement of bonds from a cage-like to a networked structure (matrix cross-linking) strengthens the material. Film shrinkage and densification may also contribute to improved strength. A similar effect may improve the adhesion to the underlying surfaces by promoting cross-linking between the lower layers of the deposited film and the underlying surface (see Figure 1).

              Because the bombardment occurs after the film has been completely deposited, this technique has drawbacks. The film shrinks typically 5-10% for a 0.5 to1-mm thick film. When the bombardment occurs after deposition completion, stress builds up inside the film. The cohesive strength of the film can degrade, rendering it prone to cracking during subsequent process steps.

General description

              The disclosed method is the periodic electron bombardment of a dielectric film during its deposition. The method improves the film’s mechanical properties and/or adhesion to underlying surfaces, such as an ES layer and/or Cu layer.

              The key elements of the method include:

•             Electron bombardment that occurs inside the dielectric deposition chamber

•             Periodic bombardment after partial ILD deposition that is repeated until the film thickness reaches the target thickness and the last ILD layer is fully treated

•             Electron bombardment just before the deposition and/or after a thin layer of film is deposited to improve adhesion of ILD to the underlying ES layer

•             In the case of ES deposition, electron bombardment just before deposition and/or after a thin layer of ES is deposited to improve adhesion of ES to the underlying ILD or Cu layer

•             Deposition process interruption during electron bombardment to accommodate differences in process conditions for deposition and bombardment (such as chamber pressure) and/or hardware limitations

Advantages

              The disclosed method provides advantages, including:

•             Improved performance due to increasing the ILD mechanical strength

•             Improved performance due to improving the adhesion of the ILD to the underlying ES

•             Improved performance due to improving the adhesion of the ES to the underlying ILD

•             Improved performance due to improving the adhesion of the ES to the underlying Cu

Detailed description

              The disclosed method is periodic electron bombardment which increases film thickness. The volume change is gradual and leads...