Browse Prior Art Database

Pads Creating Topography for Aluminum Alignment Purposes

IP.com Disclosure Number: IPCOM000248987D
Publication Date: 2017-Jan-25
Document File: 2 page(s) / 28K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to make patterning possible for Aluminum masks after flat Aluminum deposition such that the alignment marks of the lower stack levels are optically visible. The novel solution is to create an artificial topography into the deposited Aluminum surface by stacking one or more topography defined alignment marks in the lower via and metallization levels.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 54% of the total text.

Title Pads Creating Topography for Aluminum Alignment Purposes Abstract Disclosed is a method to make patterning possible for Aluminum masks after flat Aluminum deposition such that the alignment marks of the lower stack levels are optically visible. The novel solution is to create an artificial topography into the deposited Aluminum surface by stacking one or more topography defined alignment marks in the lower via and metallization levels. Problem After flat Aluminum deposition, alignment marks of the lower stack levels are not optically visible through the aluminum. Therefore, patterning is not possible for the Aluminum masks, in the lack of any visible marks. Solution/Novel Contribution The novel solution is to create an artificial topography into the deposited Aluminum surface by stacking one or more topography defined alignment marks in the lower via and metallization levels. Method/Process The novel method works based on the following concepts (not described in the order of execution). Using the design pattern, insert a wide trench in the last via layer before the Aluminum deposition. Additionally, use a wide trench in the last metal layer below the last via layer before the Aluminum deposition. Each trench must be wide enough that the copper fill during plating leaves a topography. Eventual further polish steps generate further dishing and do not completely remove the topography. The method is applicable on further via and metal layers below the last metal layer, bel...