Compositions – Etching or brightening compositions
Reexamination Certificate
2000-07-05
2003-06-24
Goudreau, George (Department: 1763)
Compositions
Etching or brightening compositions
C252S079200, C252S079300, C252S079400, C252S079500
Reexamination Certificate
active
06582623
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention concerns a CMP composition comprising a dispersion of silane modified metal oxide abrasive particles that are the product of the combination of an abrasive having surface metal hydroxides and a silane compound including at least one non-hydrolyzable substituent. This invention is also a method for using silane modified abrasive particle dispersions to polish features associated with a substrate surface as well as methods of polishing substrate features using abrasive containing polishing pads that have been modified with silane solutions.
(2) Description of the Art
Great advances are being made in the miniaturization of electronic components used in the computer and electronic industries. The miniaturization of electronic components typically involves depositing, etching and/or polishing multiple metal and oxide layers to build up an electronic substrate. Miniaturization however has created component quality concerns, many of which are overcome by precisely polishing the computer and electronic substrate materials. In order to polish electronic component surfaces precisely it has become necessary to develop chemical mechanical polishing slurries that are compatible with the combination of surfaces being polished.
One component of chemical mechanical polishing slurries that has seen very little improvement is the abrasive. Typically, metal oxide abrasives are used in chemical mechanical polishing slurries. Little effort has been made to improve slurry abrasives other than refining the abrasive particle size or the types of abrasive particles used in the slurries.
Recently, there have been several attempts to modify the surface chemistry of abrasive particles. For example, U.S. Pat. No. 5,645,736 discloses a method for polishing a work piece that uses organopolysiloxane polymers to disperse and hold the abrasive particles in a temporary film or matrix on the substrate being polished. U.S. Pat. No. 5,767,106 discloses a polishing composition including abrasive particles that have been combined with organo metallic compounds such as &ggr;-aminopropyl triethoxy silane. The particles are subsequently used in a slurry to polish a semiconductor device.
Despite these improvements, there remains a need for chemical mechanical polishing compositions that can be tailored to polish specific combination of metal and/or oxide layers associated with an electronic substrate. More particularly, there remains a need for abrasive particles that can be tailored to polish specific metal and/or dielectric layers at controlled rates while minimizing substrate defectivity.
SUMMARY OF THE INVENTION
The present invention includes a chemical mechanical polishing composition comprising a dispersion of silane modified abrasive particles that are the product of the combination of at least one metal oxide abrasive that includes at least one surface metal hydroxide and at least one silane compound the includes at least one non-hydrolyzable substituent.
In another embodiment, this invention is a chemical mechanical polishing composition comprising a dispersion including at least one silane modified abrasive particle that is the product of the combination of a metal oxide abrasive having at least one surface metal hydroxide and at least one silane compound having the formula:
Y—Si—(X
1
X
2
R)
dimers, trimers and oligomers thereof, wherein Y is hydroxy (—OH) or a hydrolyzable substituent, X
1
and X
2
are each independently selected from hydroxy, a hydrolyzable substituent, and a non-hydrolyzable substituent, and R is a non-hydrolyzable substituent wherein each non-hydrolyzable substituent is independently selected from the group consisting of alkyl, cycloalkyl, aromatic, functionalized alkyl, functionalized aromatic, and functionalized cycloalkyl, each of which may be substituted with one or more atoms selected from oxygen, nitrogen, sulfur, phosphorous, halogen and combinations thereof wherein the silane is not an aminosilane.
In yet another embodiment, this invention includes methods for polishing a substrate that includes at least one surface feature. The method includes the steps of preparing a chemical mechanical polishing slurry comprising a solution selected from water and an organic solvent, and the combination of metal oxide abrasives including at least one surface metal hydroxide and at least one silane compound that includes at least one non-hydrolyzable substituent to give a silane modified abrasive particle. The polishing slurry is then applied to a polishing pad, the substrate feature is brought into contact with the polishing pad, and the substrate surface feature is moved in relationship to the polishing pad until at least a portion of the feature is removed from the substrate.
In yet another embodiment, this invention is a method for preparing a polishing pad for polishing comprising the steps of applying a silane solution to an polishing pad including at least one abrasive particle that includes a surface metal hydroxide to form a silane modified abrasive particle, bringing a substrate including at least one surface feature into contact with the polishing pad, and moving the substrate in relationship to the polishing pad to remove at least a portion of the surface of the feature from the substrate.
The compositions and methods of the present invention have been found to provide controllable polishing characteristics to both the dielectric layer and metal layer of an integrated circuit.
DESCRIPTION OF THE CURRENT EMBODIMENT
The present invention relates to chemical mechanical polishing compositions comprising a dispersion of silane modified abrasive particles that are the product of the combination of at least one metal oxide abrasive particle including at least one surface metal hydroxide and at least one silane compound that includes at least one non-hydrolyzable substituent. This invention is also a method for polishing a substrate feature using a dispersion of silane modified abrasive particles. This invention further includes methods for using silane solutions to modify abrasives in abrasive containing polishing pads.
The term “substrate feature” as it is used herein refers to electronic substrate features such as vias and copper interconnect lines, and to layers of materials deposited on or in the features such as dielectric layers, low-k material layers, adhesion layers, metal layers, and so forth. The polishing compositions of this invention are useful for polishing substrates to remove material layers, as well as for polishing exposed substrate features.
Abrasives that are useful in the CMP compositions of this invention must include at least one surface metal hydroxide compound. The term “surface metal hydroxide compound” refers to the structure P—OH wherein P refers to the abrasive particle. In addition, the surface metal hydroxide compound must be accessible to one or more silane containing compounds in order to form the silane modified abrasives of this invention. Thus, preferred surface metal hydroxide compound containing abrasives of this invention may be selected from metal oxide abrasives including alumina, titania, zirconia, germania, silica, ceria, tantalum oxide (TaO
x
), mixtures thereof, and chemical admixtures thereof. The term “chemical admixture” refers to particles including atomically mixed or coated metal oxide abrasive mixtures. A most preferred metal oxide abrasive is silica (silicon dioxide).
The abrasive particles useful in this invention may consist of metal oxide aggregates or individual single particles. The term “particle” as it is used herein refers to both aggregates of more than one primary particle and to single particles. Preferred metal oxide particles are silica and aluminum with silica being most preferred.
The metal oxide abrasives used in the present invention may be produced by any techniques known to those skilled in the art to give abrasive particles having the characteristics reported above. Metal oxide abrasives useful in this invention are derived from processes including
Grumbine Steven K.
Streinz Christopher C.
Wang Shumin
Cabot Microelectronics Corporation
Goudreau George
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