Cleaning and liquid contact with solids – Processes – For metallic – siliceous – or calcareous basework – including...
Reexamination Certificate
1999-12-20
2001-01-09
Ogden, Necholus (Department: 1751)
Cleaning and liquid contact with solids
Processes
For metallic, siliceous, or calcareous basework, including...
C134S002000, C134S038000, C134S041000, C134S042000, C510S175000, C510S176000, C510S178000, C510S465000, C510S467000
Reexamination Certificate
active
06171405
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to cleaning solutions, and more particularly to cleaning solutions for use with integrated circuit substrates.
BACKGROUND OF THE INVENTION
An integrated circuit is typically fabricated by processing various thin films on a substrate. The thin films are usually formed, for example, through etching, ion implantation, and chemical mechanical polishing processes. During the above processes, contaminants such as sidewall polymers or fences may be produced, often as a result of the reaction between a conductive layer, a photoresist, and an etching gas typically used to process the conductive layer (e.g., an aluminum layer, a titanium layer, an aluminum—silicon layer, a tungsten layer, a tungsten—titanium layer, and a titanium-nitride layer). As a result, the yield and reliability of the ultimate product may be adversely impacted. Additionally, as the integration level of integrated circuit devices increases along with heightened production speeds, the presence of the above-mentioned contaminants may be disadvantageous. In view of the above, there is a perceived need to more effectively remove the contaminants from the devices.
FIGS. 1 and 2
describe a conventional cleaning method subsequent to: (1) a step for forming a contact hole which exposes a conductive layer by dry etching or (2) a step for patterning a conductive layer. Reference numeral
10
denotes a integrated circuit substrate such as a semiconductor substrate, reference numeral
20
denotes an interlayer insulation layer, reference numeral
30
denotes a conductive layer, reference numeral
30
A denotes a conductive layer pattern, reference numeral
40
denotes an oxide layer, reference layer
50
denotes a contact hole, and reference numeral
60
denotes a contaminant. In particular,
FIG. 1
illustrates semiconductor substrate
10
having a contact hole
50
formed thereon, which is conventionally cleaned with a photoresist stripper or an organic stripper.
Typically, contaminants such as etching-residues are removed from the sidewalls and bottom of the contact hole
50
by dipping the integrated circuit substrate in the conventional cleaning solution at a temperature ranging from 60° C. to 90° C. The conventional cleaning solution remaining on the surface of the semiconductor substrate may be removed by dipping the integrated circuit substrate into an alcohol-containing rinser, and then dipping the substrate into deionized water. Next, contaminants remaining on the surface of the integrated circuit substrate can be removed by dipping the substrate into a second deionized water bath. Thereafter, the substrate is usually spun to remove deionized water remaining on the surface of the substrate.
A number of problems may be associated with using a conventional cleaning solution. A conventional cleaning solution such as a photoresist stripper or an organic stripper may be limited in its ability to remove etching residues or other contaminants which can adhere to a surface of a contact hole. As a result, the cleaning may not be effective, and a portion of contaminant
60
can remain on the sidewalls and bottom of the contact hole as shown in FIG.
1
. In particular, organometallic sidewall polymers are often oxidized into oxo-metallic complexes by a process of plasma ashing which is carried out in order to remove a photoresist. It is often difficult to effectively remove these oxo-metallic complexes using conventional cleaning solutions.
In addition, this conductive layer may be susceptible to corrosion as a result of using a conventional cleaning solution. Referring to
FIG. 2
, a conductive layer pattern
30
A can be partially etched during the cleaning process, thus potentially deforming the profile of the conductive layer pattern. The corrosiveness of the cleaning solution may reduce the life spans of pipes and other cleaning equipment used in conjunction with the cleaning solutions. Additionally, a separate rinsing process may be required between the application of the cleaning solution and the deionized water rinsing process. As a result, manufacturing processes may become increasingly complex. Since a conventional cleaning solution itself may contain a sizeable number of metal ions and contaminants, the metal ions and contaminants may adhere to the surface of the integrated circuit substrate during the cleaning process.
Thus, there is a need in the art to address the problems associated with conventional cleaning solutions.
SUMMARY OF THE INVENTION
In one aspect, the invention relates to cleaning solutions for removing contaminants from integrated circuit substrates. The cleaning solutions comprise fluoroboronic acid and phosphoric acid.
In a second aspect, the invention relates to methods for removing contaminants from integrated circuit substrates. The methods comprise first contacting the integrated circuit substrates with cleaning solutions comprising fluoroboric acid and phosphoric acid. Subsequently, the integrated circuit substrates are contacted with aqueous solutions to remove the contaminants.
The invention provides potential advantages over conventional cleaning solutions and methods of using the same. For example, the cleaning solutions may allow for the selective removal of a number of contaminants with minimal corrosiveness to the integrated circuit substrates. Additionally, the methods of the invention may allow for the integrated circuit substrate to be cleaned using fewer steps that in conventional methods. As a result, increased productivity of integrated circuit substrates may be realized.
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Mruk Brian P.
Myers Bigel Sibley & Sajovec P.A.
Ogden Necholus
Samsung Electronics Co,. Ltd.
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