Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-08-11
2001-04-24
Delcotto, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S175000, C510S245000, C510S255000, C510S264000, C510S488000, C510S499000
Reexamination Certificate
active
06221818
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a stripping and cleaning composition and process for removal of polymeric materials and organic, organometallic and metal oxide residues from substrates. More particularly, it relates to such a composition and process for removing polymers, such as photoresist, polyimide, and the like and etching residues after plasma etching processes in the fabrication of integrated circuits and similar processes. Most especially, it relates to such a composition and process which is effective for the removal of these materials while avoiding substantial attack on metal layers employed in integrated circuits, including titanium layers.
2. Description of the Prior Art
As integrated circuit manufacturing has become more complex and the dimensions of circuit elements fabricated on silicon or other semiconductor wafers have become smaller, continued improvement in techniques used to remove photoresist or other polymeric materials and residues formed from such materials has been required. Photoresist or other polymeric materials, such as polyimide, are often subjected to ion implantation, plasma etching, reactive ion etching or ion milling during the fabrication processes to define patterns in the substrate. Additionally, oxygen plasma oxidation is often used for removal of photoresist or other polymeric materials after their use during the fabrication process has been completed. Such high energy processes typically result in the hardening of the photoresist and the formation of organometallic and other residues on sidewalls of the structures being formed in the fabrication process.
A variety of metal and other layers are commonly employed in integrated circuit fabrication, including aluminum, aluminum/silicon/copper, titanium, titanium nitride, titanium/tungsten, tungsten, silicon oxide, polysilicon crystal, and the like. The use of such different layers results in the formation of different organometallic residues in the high energy processes. In addition to being effective for removing photoresist or other polymeric materials or residues, stripping and cleaning compositions should also not attack the different metallurgies used in integrated circuit fabrication.
SUMMARY OF THE INVENTION
Hydroxylamine based compositions, as described in the above-referenced predecessor applications and issued patents, and which are commercially available from EKC Technology, Inc., the assignee of this application, have been proven as very efficient photoresist and etching residue removing formulations in the integrated circuit industry. As a result of a continuous effort to decrease critical dimension size in the integrated circuit industry, such as in the fabrication of sub-micron size devices, etching residue removal and substrate compatibility with chemicals employed in wet processing is becoming more and more critical for obtaining acceptable yield in very large scale integration (VLSI) and ultra large scale integration (ULSI) processes. The composition of such etching residue is generally made up of the etched substrates, underlying substrate, photoresist and etching gases. The substrate compatibility of the wafers with wet chemicals, such as the hydroxylamine compositions, is highly dependent on the processing of the polysilicon, multilevel interconnection dielectric layers and metallization in thin film deposition, etching and post-etch treatment of the wafers, which are often quite different from one fabrication process to another.
In some circumstances, hydroxylamine compositions, such as those containing catechol (1,2-dihydroxybenzene), have produced corrosion on certain metal substrates, such as those including a titanium metal layer, or those including an aluminum layer at high temperatures, i.e. in excess of 65° C. Titanium has become more widely used in semiconductor manufacturing processes. It is employed both as a barrier layer to prevent electromigration of certain atoms and as an antireflector layer on top of other metals. Catechol is considered a hazardous material under applicable Federal regulations (SERA Title III). In a drive to introduce more effective and less toxic wet chemical products for the semiconductor industry, research has been carried out to find a suitable replacement for catechol in hydroxylamine compositions.
Accordingly, it is an object of this invention to provide an improved hydroxylamine based composition and process using such a composition suitable for meeting current semiconductor fabrication requirements.
It is another object of the invention to provide such a composition and process which is suitable for removing photoresist and other polymeric materials and residues from wafers and other substrates including one or more titanium metal layers without substantial attack on such titanium layers.
It is a further object of the invention to provide such a composition and process which contains more healthy and environmentally friendly chemicals.
The attainment of these and related objects may be achieved through use of the hydroxylamine-gallic compound composition and process herein disclosed. A hydroxylamine-gallic compound composition in accordance with this invention comprises a hydroxylamine compound, at least one alcohol amine compound which is miscible with the hydroxylamine compound and a gallic compound. A process for removing photoresist or other polymeric material or a residue from a substrate in accordance with this invention comprises contacting the substrate with a composition that contains a hydroxylamine compound, an alcohol amine compound which is miscible with the hydroxylamine compound and a gallic compound for a time and at a temperature sufficient to remove the photoresist, other polymeric material or residue from the substrate.
In practice, we have found that substitution of a gallic compound in approximately equivalent amounts for catechol gives a photoresist stripping and cleaning or residue removing composition that attacks titanium at least about three times less than the composition containing catechol. At the same time, the gallic compound containing composition gives equivalent performance as a photoresist stripping and cleaning or residue removing composition.
The attainment of the foregoing and related objects, advantages and features of the invention should be more readily apparent to those skilled in the art, after review of the following more detailed description of the invention, taken together with the drawings, in which:
REFERENCES:
patent: 5334332 (1994-08-01), Lee
patent: 5419779 (1995-05-01), Ward
patent: 5672577 (1997-09-01), Lee
patent: 5902780 (1999-05-01), Lee
patent: 6121217 (2000-09-01), Lee
patent: 6140287 (2000-10-01), Lee
Delcotto Gregory
EKC Technology, Inc.
Pennie & Edmonds LLP
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