Browse Prior Art Database

Fully Self-Aligned Via Process

IP.com Disclosure Number: IPCOM000247632D
Publication Date: 2016-Sep-21
Document File: 5 page(s) / 108K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a structure for a fully self-aligned via for which all edges are self-aligned and a method for making the same.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 60% of the total text.

Page 01 of 5

Title

Fully Self-Aligned Via Process

Abstract

Disclosed is a structure for a fully self-aligned via for which all edges are self-aligned and a method for making the same.

Problem

A self-aligned via (SAV) has two self-aligned sides and two non-self-aligned sides. The non-self-aligned sides tend to have a lower chamfer angle than the SAV side does, which results in shorts to the metal below.

Figure 1: Problem

The via near metal above the inner vertex usually requires a larger design space.

Figure 2: Problem, cont'd.

Current process flow:


1. My PR (y=x+1)

2. My litho, TiN HM open


3. Vx PR

4. Vx RIE, using TiN HM


Page 02 of 5


5. Vx PR removal

6. My trench RIE

7. My HM removal

8. My and Vx metal fill CMP

One via litho, and one metal litho

Solution/Novel Contribution

The novel contribution is a structure for a fully self-aligned via for which all edges are self-aligned and a method for making the same.

Figure 3: Fully self-aligned via

Method/Process

Process Flow - modified

1. Mxb litho exposure to form vertical shape opening

2. Hardmask (HM)_Mxb open (define two SAV edges in vertical direction), Titanium Nitride (TiN) HM open, selective to Mxa Tetraethyl orthosilicate (TEOS)

3. My litho exposure to form horizontal metal shape

4. HM_My open, SiN HM open, selective to Mxb TiN and Mxa TEOS, (the latter may not be very critical)

5. Vx Reactive Ion Etch (RIE) (through Interlayer Dielectric (ILD) using HM_Mxb and HM_My to form fully-self-aligned via,) selective to both TiN...