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Submicron Sidewall Fabrication Utilizing Aluminum Anodization

IP.com Disclosure Number: IPCOM000044488D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Ogura, S: AUTHOR [+2]

Abstract

This article describes a process which consists of anodizing aluminum to form an Al2O3 sidewall for the production of submicron features in integrated circuit manufacturing. A blanket of aluminum is deposited over a thin layer of SiO2 (Fig. 1). A layer of low temperature, CVD (chemical vapor deposition) SiO2 is deposited over the aluminum. A mask is used to pattern the SiO2 and aluminum. The resist is left on to prevent anodization of the aluminum through pin holes in the CVD SiO2 . The wafer is placed in a bath of oxalic acid solution or a solution of NH3OH. A voltage is applied to the wafer, and Al2O3 is formed on the exposed aluminum sidewall (Fig. 2). The applied potential controls the thickness (lateral dimension) of the Al2O3. Removal of the resist, aluminum, and CVD SiO2 leaves a free-standing Al2O3 stud (Fig. 3).

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Submicron Sidewall Fabrication Utilizing Aluminum Anodization

This article describes a process which consists of anodizing aluminum to form an Al2O3 sidewall for the production of submicron features in integrated circuit manufacturing. A blanket of aluminum is deposited over a thin layer of SiO2 (Fig.
1). A layer of low temperature, CVD (chemical vapor deposition) SiO2 is deposited over the aluminum. A mask is used to pattern the SiO2 and aluminum. The resist is left on to prevent anodization of the aluminum through pin holes in the CVD SiO2 . The wafer is placed in a bath of oxalic acid solution or a solution of NH3OH. A voltage is applied to the wafer, and Al2O3 is formed on the exposed aluminum sidewall (Fig. 2). The applied potential controls the thickness (lateral dimension) of the Al2O3. Removal of the resist, aluminum, and CVD SiO2 leaves a free-standing Al2O3 stud (Fig. 3). This process solves two problems associated with oxidizing polysilicon to form an oxide sidewall of a desired lateral dimension or thickness. They are: 1. Relatively high temperatures that are required. 2. Relatively low cycle times to achieve the desired lateral dimension.

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