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Multilayer Permanent Hard Mask to Improve Reliability and lower Resistor Capacitor (RC) for Back End of Line (BEOL) Interconnects

IP.com Disclosure Number: IPCOM000235792D
Publication Date: 2014-Mar-25
Document File: 2 page(s) / 96K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to use a multi-layer Permanent Hard Masks (PHM) to improve reliability. A thin layer of Tetraethyl Orthosilicate (TEOS) is used on top of a thin layer of NBLoK as a PHM.

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Page 01 of 2

Title

Multilayer Permanent Hard Mask to Improve Reliability and lower Resistor Capacitor (RC) for Back End of Line (BEOL) Interconnects

Abstract

Disclosed is a method to use a multi-layer Permanent Hard Masks (PHM) to improve reliability. A thin layer of Tetraethyl Orthosilicate (TEOS) is used on top of a thin layer of NBLoK as a PHM.

Problem

Two materials have been tried as Permanent Hard Masks (PHM). One is Tetraethyl Orthosilicate (TEOS). The advantage of TEOS is the Chemical Mechanical Planarization stop on the TEOS that is developed. The Time-Dependent Dielectric Breakdown (TDDB) improved over the Power-On Reset (POR) process (i.e. stop in Ultra-Low K (ULK)). The other material is NBLoK. The advantage of NBLoK is the CMP stop on NBLoK that is developed. The TDDB is improved over the TEOS PHM and the POR process (i.e. stop in ULK).

Figure 1: Standard/Existing Process Flow for PHM Integration


• Keeping PHM in place helps improve TDDB

• CMP stop on PHM is challenging, leaving few options for PHM material choice

Two main problems exist with these materials. Thick NBLoK PHM is required and the NBLoK has a high K value, which results in higher capacitance. The use of TEOS and NBLoK alone as PHM shows benefits, but a method is needed to use a multi-layer PHM to improve reliability with no Resistor Capacitor (RC) impact.


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Solution/Novel Contribution

The solution is to use a multi-layer PHM to improve reliability. A thin layer of TEOS is used on top...