Abrasive tool making process – material – or composition – With synthetic resin
Reexamination Certificate
2001-05-18
2003-10-14
Marcheschi, Michael (Department: 1755)
Abrasive tool making process, material, or composition
With synthetic resin
C106S003000, C051S307000, C051S308000, C051S309000
Reexamination Certificate
active
06632259
ABSTRACT:
This invention relates to the use of certain engineered copolymers for chemical mechanical polishing (CMP) of semiconductor (and similar-type) substrates and methods relating thereto.
Broadly speaking, CMP is an enabling technology for the production of semiconductor structures and is an effective method for the removal and planarization of thin films or layers on semiconductor substrates during their production. Such semiconductor substrates often contain integrated circuits, such as, multi-chip modules, capacitors and the like. During the CMP process, a slurry or substantially particle-free polishing fluid (collectively referred to herein as a polishing composition) is used along with a polishing pad. The polishing pad motion (relative to the semiconductor substrate) in combination with the polishing fluid's chemical reaction with the substrate surface generally results in material removal from the semiconductor substrate surface.
Semiconductor substrates used to make integrated circuits typically contain three different layers: (i) a conductive metal layer; (ii) a barrier (or liner) film between the conductive metal layer and the underlying dielectric layer; and (iii) an underlying dielectric layer typically having recessed metal lines (metal interconnects) that form the circuit interconnects in the integrated circuit.
The term “dishing” refers to excessive (unwanted) removal of metal from the metal interconnect precursors during CMP, thereby causing unwanted cavities in the interconnect structure. Dishing is undesirable, since it negatively affects the electrical performance of the semiconductor structure (integrated circuit). Similarly, the term “erosion” refers to excessive removal of dielectric material surrounding metal interconnects during CMP. Erosion is undesirable, since the dielectric layer should ideally be flawless and free of cavities to ensure optimal electrical performance of the semiconductor structure (integrated circuit).
CMP is typically used to polish the semiconductor substrate to a smooth planar polished surface on which are manufactured successive layers, which themselves can be polished by CMP. Thus, excessive dishing of interconnects (recessed in the underlying dielectric layer) and erosion of the dielectric layer surrounding the interconnects in the first layer can manifest as defects in a successive layer of a multi-layered semiconductor substrate. Semiconductors having copper circuits can be particularly difficult to polish using conventional polishing compositions, polishing pads and techniques.
The use of polyacrylic acid and polymethacrylic acid for CMP of semiconductor wafers is disclosed in U.S. Pat. No. 6,117,775.
This invention is directed to the use of certain engineered copolymers for enhanced removal of metal during CMP of semiconductor substrates, and such use can also often provide suppression of dishing in metal interconnects in semiconductor substrates. The engineered copolymer molecules for use in this invention can comprise a first moiety having at least one hydrophilic functional group such as carboxyl, hydroxyl, halogen, phosphonate, phosphate, sulfonate, sulfate, nitro and the like and a second moiety which is less hydrophilic than the first moiety. The second moiety can comprise one or more hydrophobic functional groups. The first moiety of the engineered copolymer molecules of this invention will typically align or otherwise forms bonds (preferably coordinate covalent bonds) with the substrate surface. Depending upon the embodiment selected, the second moiety of the engineered copolymer molecules often provides structural rigidity to the engineered copolymer molecules and can also enable interaction of the engineered copolymer molecules with the polishing pad surface.
Thus, the methods and compositions of this invention generally enhance the removal rate of metal from a substrate surface containing metal interconnects during CMP, while also typically minimizing dishing of the metal interconnects through controlled contact-mediated reactions between the substrate surface and the polishing pad surface.
In an embodiment, this invention is directed to suppression of dishing and enhanced clearing of metal during CMP of semiconductor or similar-type substrates, particularly substrates with metal interconnects. The polishing compositions of this embodiment preferably contain engineered copolymer molecules and can be used to polish semiconductor or similar-type substrates utilizing commercially available or the like polishing pads.
The term “engineered” means that the copolymers for use in the methods of this invention are derived by a judicious choice of monomers. In an embodiment, the copolymer for use in the method of this invention is engineered from monomers to contain hydrophilic functional groups that readily form strong bonds, e.g. coordinate covalent bonds, with the substrate surface. In this embodiment, the hydrophobic functional groups provide structural rigidity to the copolymer molecule and optionally also interact with the polishing pad surface through van der Waals forces or other interactions. The engineered copolymer enhances the removal rate of metal from the substrate surface during CMP, while minimizing dishing of metal interconnects through controlled contact-mediated reactions.
In an embodiment, hydrophilic functional groups are ionizable functional groups while the hydrophobic functional groups are non-ionizable functional groups. The term “up to” as used herein is intended to include zero as a lower limit and to further include the identified value as an upper limit (and all values in between), i.e., “up to about X,” means values in a continuous range including 0 up to a value which may not be precisely X but which would be deemed to be sufficiently close to X as a practical matter to those skilled in the art, depending upon the particular embodiment or end use under consideration. Additionally, all percentages are on a weight basis unless otherwise specified.
In an embodiment, the method of this invention is performed on semiconductor substrates containing metal interconnects, preferably copper interconnects, utilizing a reactive liquid comprising a blend of one or more engineered copolymers. The copolymers are preferably present up to about 1% by weight, and each copolymer is derived from a mixture of monomers having hydrophilic functional groups and relatively less hydrophilic (hydrophobic) functional groups. The reactive liquid of this embodiment may also include: (i) up to about 15% by weight of an oxidizing agent; (ii) up to about 2% by weight of a corrosion inhibitor; and (iii) up to about 3% by weight of a complexing agent.
In an embodiment, the method of this invention is performed on semiconductor substrates containing metal interconnects, preferably copper interconnects, utilizing a reactive liquid having a pH under about 5.0, preferably in a range of about 2.8 to about 4.2, more preferably in a range of about 2.8 to about 3.8. The reactive liquid can comprise a blend of one or more engineered copolymers, typically up to about 1% by weight. Each copolymer is typically derived from a mixture of monomers having hydrophilic functional groups and hydrophobic (relatively less hydrophilic) functional groups. The reactive liquid of this embodiment may also include: (i) up to about 15% by weight of an oxidizing agent; (ii) up to about 2% by weight of a corrosion inhibitor; and (iii) up to about 3% by weight of a complexing agent.
In an embodiment, the method of this invention is performed on a semiconductor substrate containing metal interconnects, preferably copper interconnects, utilizing a reactive liquid comprising: (i) up to about 1% by weight of an engineered copolymer derived from an acrylic acid monomer and methacrylic acid monomer at a mole ratio in a range of about 1:20 to about 20:1, preferably 1:1; (ii) up to about 15% by weight of an oxidizing agent; (iii) up to about 2% by weight of a corrosion inhibitor; and (iv) up to about 3% by weight of a complexing agent.
In an embodiment, the meth
Ghosh Tirthankar
Weinstein Barry
Biederman Blake T.
Marcheschi Michael
Ramana Anuradha
Rodel Holdings Inc.
LandOfFree
Chemical mechanical polishing compositions and methods... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Chemical mechanical polishing compositions and methods..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chemical mechanical polishing compositions and methods... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3157093