Compositions – Etching or brightening compositions
Reexamination Certificate
2000-09-05
2002-09-10
Utech, Benjamin L. (Department: 1765)
Compositions
Etching or brightening compositions
C252S079400, C438S692000
Reexamination Certificate
active
06447695
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an aqueous dispersion composition for chemical mechanical polishing for use in the manufacture of semiconductor devices (hereunder referred to as “aqueous dispersion composition for chemical mechanical polishing”, or sometimes simply as “aqueous dispersion composition”). More specifically, the invention relates to an aqueous dispersion composition for chemical mechanical polishing that, for polishing of different types of working films and barrier metal layers formed on semiconductor substrates, can accomplish efficient polishing particularly of barrier metal layers and can give adequately flattened and high precision finished surfaces.
2. Description of the Prior Art
A recent technique used in the manufacture of semiconductor devices is a process whereby a wiring material such as tungsten, copper or the like is embedded in a hole or groove formed in an insulating film on a processing wafer and then polishing is performed to remove the wiring material above the surface of the insulating film to thereby complete formation of the wiring. Wiring formed by this process is called damascene wiring. This polishing cannot be very efficiently achieved on barrier metal layers made of metals with high hardness such as tantalum and the like. On the other hand, relatively soft wiring materials such as copper are easy to polish but exhibit dishing in the wiring sections, making it difficult to produce flat finished surfaces. In cases with a high pH, particularly with porous insulating films of low dielectric constant, the insulating film is excessively polished making it impossible to form satisfactory damascene wiring.
SUMMARY OF THE INVENTION
[Problems to Be Solved by the Invention]
The present invention solves the aforementioned problems of the prior art by providing a useful aqueous dispersion composition for chemical mechanical polishing in the manufacture of semiconductor devices, which is able to polish barrier metal layers made of tantalum and the like with sufficient rate, which gives sufficiently flat finished surfaces without excessively polishing wiring materials made of copper or the like or excessively polishing insulating films, and which can form satisfactory damascene wiring.
[Features of the Invention]
The aqueous dispersion composition for chemical mechanical polishing of the present invention is characterized by comprising a polishing agent, water and a polishing rate adjustor.
More, the aqueous dispersion composition for chemical mechanical polishing for use in the manufacture of semiconductor devices according to the another present invention, is characterized by comprising a polishing agent, water and a polishing rate adjustor, wherein, when polishing a copper film, a tantalum layer and/or tantalum nitride layer and an insulating film under the same conditions, the ratio (R
Cu
/R
Ta
) between the polishing rate of the copper film (R
Cu
) and the polishing rate of the tantalum layer and/or tantalum nitride layer (R
Ta
) is no greater than {fraction (1/20)}, and the ratio (R
Cu
/R
In
) between the polishing rate of the copper film (R
Cu
) and the polishing rate of the insulating film (R
In
) is from 5 to ⅕.
[Effect of the Invention]
According to the invention it is possible to obtain a useful aqueous dispersion composition for chemical mechanical polishing by preparing an aqueous dispersion composition containing a polishing rate adjustor.
By specifying the ratio between the polishing rates of for a copper film and a tantalum layer and/or tantalum nitride layer and the ratio between the polishing rates for a copper film and an insulating film, it is possible to polish barrier metal layers at a sufficient rate, to polish working films at an appropriate rate and to obtain an aqueous dispersion composition for chemical mechanical polishing which is useful for the manufacture of semiconductor devices, without excessive polishing of insulating films and without dishing.
Moreover, by specifying the function of the polishing rate adjustor or the type of polishing rate adjustor, and by specifying the pH, it is possible to easily obtain an aqueous dispersion composition for chemical mechanical polishing according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[Means for Solving the Problems]
As a result of research with the object of obtaining an aqueous dispersion composition for chemical mechanical polishing that can achieve adequate flattening of finished surfaces for polishing of working films formed on semiconductor substrates, it was found that by including a polishing rate adjustor comprising a heterocyclic compound with an amino group and the like, it is possible to accelerate polishing of barrier metal layers, inhibit polishing of wiring materials such as copper, and to obtain adequately flattened and highly precise finished surfaces without excessive polishing of insulating films. The present invention has been accomplished on the basis of this finding.
This object is achieved firstly by an aqueous dispersion composition containing a polishing rate adjustor. The object is achieved secondly by an aqueous dispersion composition for chemical mechanical polishing with a specified ratio between the polishing rates of a copper film and a tantalum layer and/or tantalum nitride layer and between the polishing rates of a copper film and an insulating layer. The object is achieved thirdly by an aqueous dispersion composition containing a polishing rate adjustor with a specific function. The object is achieved fourthly by an aqueous dispersion composition containing a specific heterocyclic compound as the polishing rate adjustor. The object is achieved fifthly by an aqueous dispersion composition with a specific pH.
The aqueous dispersion composition for chemical mechanical polishing of the present invention is characterized by comprising a polishing agent, water and a polishing rate adjustor.
More, the aqueous dispersion composition for chemical mechanical polishing for use in the manufacture of semiconductor devices according to the another present invention, is characterized by comprising a polishing agent, water and a polishing rate adjustor, wherein, when polishing a copper film, a tantalum layer and/or tantalum nitride layer and an insulating film under the same conditions, the ratio (R
Cu
/R
Ta
) between the polishing rate of the copper film (R
Cu
) and the polishing rate of the tantalum layer and/or tantalum nitride layer (R
Ta
) is no greater than {fraction (1/20)}, and the ratio (R
Cu
/R
In
) between the polishing rate of the copper film (R
Cu
) and the polishing rate of the insulating film (R
In
) is from 5 to ⅕.
The copper which may form the “copper film” includes not only pure copper, but also alloys containing at least 95 wt % copper, such as copper-silicon, copper-aluminum and the like. The tantalum which may form the “tantalum layer” is also not limited to pure tantalum, and includes tantalum-containing alloys such as tantalum-niobium. The tantalum nitride which may form the “tantalum nitride layer” is also not limited to pure products.
The phrase “under the same conditions” used above means that the same polishing apparatus model is used, and the disk and head rotation rate, the polishing pressure, the polishing time, the type of polishing pad used and the rate of supply of the aqueous dispersion composition per unit of time are all consistent.
The “ratio” of the polishing rates referred to above can be calculated from the respective polishing rates obtained by separately polishing a copper film, a tantalum layer and/or tantalum nitride layer and an insulating film, under the same conditions. The polishing may be carried out using a wafer provided with the copper film, tantalum layer and/or tantalum nitride layer or insulating film.
The ratio (R
Cu
/R
Ta
) between the polishing rate of a copper film (R
Cu
) and the polishing rate of a tantalum layer and/or tantalum nitride layer (R
Ta
) is preferably no greater tha
Hattori Masayuki
Kawahashi Nobuo
Motonari Masayuki
JSR Corporation
Umez-Eronini Lynette T.
Utech Benjamin L.
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