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Method for a substrate-insensitive photoresist layer as an interaction barrier for sensitive high-performance photoresists

IP.com Disclosure Number: IPCOM000020722D
Publication Date: 2003-Dec-10
Document File: 4 page(s) / 66K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a substrate-insensitive photoresist layer as an interaction barrier for sensitive high-performance photoresists. Benefits include improved yield and improved performance.

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Method for a substrate-insensitive photoresist layer as an interaction barrier for sensitive high-performance photoresists

Disclosed is a method for a substrate-insensitive photoresist layer as an interaction barrier for sensitive high-performance photoresists. Benefits include improved yield and improved performance.

Background

         High-performance photoresists interact with underlying layers and the substrate. The result can be footing, undercutting, and other undesirable profiles (see Figure 1). This problem is addressed by using complicated schemes to mitigate substrate interactions, such as:

•         Introducing bottom antireflecting coatings (BARCs) that are defect prone (see Figure 2)

•         Adjusting photoresists to be less sensitive to substrates, at the expense of resist performance

•         Pretreating substrates to be less problematic for photoresists

         All of these techniques are dirty, complicated, or expensive.

General description

         The disclosed method is a substrate-insensitive photoresist layer as an interaction barrier for sensitive high-performance photoresists. The key elements of the method include:

•         The first exposure images the pattern into the upper layer but not the lower one because the lower resist is not sensitive to this wavelength.

•         The blanket second exposure uses the pattern already defined in the upper layer as a hard contact mask to image it into the lower layer. The upper resist layer must absorb strongly at the second wavelength to ensure adequate masking.

•         The upper resist can be a high performance resist that may have substrate interactions that preclude it from coming into direct contact with the substrate.

•         The lower resist can be an older-generation resist that does not have any substrate interactions but can image the tight geometries well because it is exposed with hard contact lithography.

Advantages

         The disclosed method provides advantages, including:

•         Improved yield due to preventing defects, such as footing, undercutting, and other undesirable profiles

•         Improved performance due to resulting in good pattern fidelity

•         Improved cost effectiveness due to using standard developers

•         Improved cost effectiveness due to using an older generation resist that is immune to substrate interactions

Detailed description

         The layer between the high-performance sensitive layer and the substrate functions as an imageable barrier layer.

         Because the lower layer is being imaged by hard contact lithography using the patt...