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Method for plate-covered laminar wafer drying

IP.com Disclosure Number: IPCOM000021715D
Publication Date: 2004-Feb-04
Document File: 4 page(s) / 76K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for plate-covered laminar wafer drying. Benefits include improved functionality, improved performance, and improved environmental friendliness.

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Method for plate-covered laminar wafer drying

Disclosed is a method for plate-covered laminar wafer drying. Benefits include improved functionality, improved performance, and improved environmental friendliness.

Background

A problem for existing dry cleaning technologies is the convergence of deposited film thickness to a monolayer. For example, as film thickness become 5-10 monolayers, 3 monolayers of unremoved water becomes a major barrier to the integrity of both the underlying and capping films. A single water monolayer is significant. Examples of a few issues that can occur because of this problem are delamination, increase of Keff in low dielectric constant (low-K) films, and corrosion.

Performance hindrance is mainly due to inefficiencies of conventional drying techniques. They involve the displacement of water and particles from the wafer surface using isopropyl alcohol (IPA). Cleaning liquids and\or gases are on one boundary in contact with the wafer surface, while the opposite boundary of the cleaning chemistry film is exposed to an essentially endless bulk of gas (such as air or N2). The differing boundaries and the resulting differing interfacial forces causes a turbulent flow across the surface of the wafer (see Figure 1).

Another problem impacting the multiwafer dry cleaning processes is throughput. The typical technique for reducing the turbulence of the cleaning chemicals (to reduce cleaning variation) is to reduce the flow rate. Reduction of flow rate is inversely proportional to cleaning time. As flow rate is reduced, cleaning takes longer.

An additional problem with existing multiwafer cleaning technologies is the inefficient use of cleaning chemicals, which results in both an increase in cost and environmental burden.

Engineering adjustments are made to turbulent flow and multiwafer technologies so that the average cleaning variation across each wafer and from wafer to wafer is minimized. The process is maximized for water removal from the wafer’s surface. Conventional multiwafer, dry cleaning technologies are nearly ineffective for the latest microprocessor technologies.

Cleaning time is an ever increasing parameter with conventional cleaning methods. No direct solution is typically available within the same technology scheme. Alternative technologies are being sought for each progressive technology generation.

While the inefficient use of chemicals in multiwafer cleaning technologies can be minimized via engineering research and control parameters, a limit exists based on the method of the technology and the tool configurations. Single wafer cleaning methods could be used to combat this situation; however, single wafer cleaning methods are a new technology in the wafer cleaning area.

General description

The disclosed method is the positioning of a covering plate, such as a shower head in wafer dry etchers with only one dispense hole at the very center. The plate is placed adjacent to the wafer surface during the dry cl...