Chemical mechanical polishing slurry, cmp process and electronic device process

Inactive Publication Date: 2007-11-22
HITACHI CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0044]The slurry for Chemical Mechanical Polishing (CMP) according to the present invention is capable of sustaining high polishing speeds and providing a sufficient polishing selectivity for achieving the planarity of the surface being processed even if the planarization additives (C) are not added by using the composite particles with a negative zeta potential as the abrasive particles. While the polishing speed drops substantially if the zeta potential of the composite particles, i.e., abrasive grains, is a positive potential, as it causes excessive adherence of planarization additives (C) even though the planarization additives are added, the slurry for CMP according to the present invention makes it possible to suppress the adherence of the planarization additives (C), thus achieving both a high polishing speed and a sufficient polish selectivity by means of using the composite particles with a negative zeta potential as the abrasive grains.
[0045]The method of producing electronic

Problems solved by technology

The slurry being used in the CMP typically consists of colloidal silica and fumed silica abrasive grains dispersed in an alkali-based solution and is applied in polishing an object by mechanical polishing by means of silica (SiO2) and a chemical etching effect, but it has many problems related to the planarity of the surface being processed, scratches, finish point control in polishing, etc.
There is a tendency in the process of producing semiconductor devices in recent years that abrasive grains used for the polishing process are becoming increasingly minute while the demand for low scratchiness is intensifying, which in turn is degrading the polishing process efficiency.
The abrasive grains produced by this method is electrostatically compounded so that the adhesive strength of the inorganic particles to the organic particles is weak and the inorganic particles tend to drop off easily, thus making it difficult to sustain sufficient polishing speeds.
Furthermore, there is also a problem that any additives applied for planarization of the polish-

Method used

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Examples

Experimental program
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embodiments

Embodiments 1-3

[0049]In all of the embodiments 1-3 according to the present invention, the slurry for CMP was based on composite particle abrasive grains produced by the dry type composite producing method compounding organic host particles of poly(methylmethacrylate) (PMMA) mono-dispersion particles (5 μm) with inorganic particles of ceria (CeO2) particles (14 nm) in such a way that the zeta potential becomes a negative potential. Since it is difficult to measure the zeta potentials of the composite particle abrasive grains thus produced as the high concentration slurry, large-sized particles and composite particles cannot be measured easily by the conventional laser Doppler method, it was measured by Matec Applied Sciences' instrument, ESA-9800, that measures the zeta potential by measuring the pressure amplitude of the high frequency vibrations caused by electrophoresis. The zeta potentials of the composite particles were −40 mV in embodiment 1, −20 mV in embodiment 2, and −5 mV ...

embodiments 4-7

[0054]Next, the relation between the concentration of the abrasive grains of composite particles and the polishing speed in the slurry for CMP was evaluated. The polishing test was conducted under similar conditions as in embodiments 1 through 3. The slurry for CMP used in embodiments 4 through 7 were composite particle abrasive grains consisting of mono-dispersion particles (5 μm) as the organic host particles of PMMA and CeO2 particles (14 nm) as the inorganic guest particles same as in embodiment 2, having the zeta potential of −20 mV. The concentration of the abrasive grains relative to water was 0.2 wt % in embodiment 4, 1.5 wt % in embodiment 5, 5 wt % in embodiment 6, and 10 wt % in embodiment 7.

[0055]While the abrasive grains of composite particles used in embodiment 2 were used both for comparative examples 4 and 5, the concentration of the abrasive grains relative to water was 0.1 wt % in embodiment 4, and 20 wt % in embodiment 5 in the polishing tests conducted similarly ...

embodiments 8-11

[0057]Next, the relation between the concentration of the abrasive grains of composite particles and the polishing speed in the slurry for CMP was evaluated. The polishing test was conducted under the same conditions. The slurries for CMP used in embodiments 8 through 11 were composite particle abrasive grains consisting of organic host particles of PMMA mono-dispersion particles and inorganic guest particles of CeO2 particles (14 nm), having the abrasive concentration of 1 wt %, while the average particle size of the PMMA mono-dispersion particles used as organic host particles was 0.3 μm in embodiment 8, 1.5 μm in embodiment 9, 5 μm in embodiment 10, and 10 μm in embodiment 11. Since the average particle diameter of the inorganic guest particles was 14 nm, sufficiently smaller than that of the host particles, so that the average particle diameter of the abovementioned PMMA mono-dispersion particles can be regarded as the average particle diameter of the composite particles, which ...

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Abstract

To provide a slurry for Chemical Mechanical Polishing, a Chemical Mechanical Polishing method using said slurry, and a method of producing electronic devices using said method that makes it possible to achieve a low scratch process capability in processing surfaces such as SiO2 film surfaces and the like and also to enable speed polishing to attain a high processing efficiency.
Slurry for Chemical Mechanical Polishing characterized in comprising abrasive grains and water, wherein said abrasive grains are composite particles coated with ceria particles consisting of organic host particles and ceria particles, zeta potential of said composite particles being a negative potential, the organic host particles constituting the composite particles coated with ceria particles are organic host particles to which carboxyl groups and sulfonyl groups are introduced; the slurry is added with panarization additive; and the planarization additive is poly(methyl)acrylic acid ammonium salt.

Description

FIELD OF THE INVENTION[0001]The invention pertains to the slurry used in the Chemical Mechanical Polishing (“CMP”) process, which is essential to the Shallow Trench Isolation (“STI”) method applied in the producing process of semiconductor devices, the CMP method using said slurry, and the method of producing electronic devices using said method, in particular, said method applied to achieve a low-scratch finish on workpieces being polished and high process efficiency simultaneously, as well as to achieve high planarity on the processed surface of the workpieces.DESCRIPTION OF THE RELATED ART[0002]Because of a trend in the design of semiconductor devices toward minute and multi-layer structures, the element removal method is making a shift from the LOCOS (Local Oxidation of Silicon) technology, in which the nitride film of the silicon surface is removed by oxidizing a portion of the surface, to the STI technology, which makes higher integration possible. The STI technology is a meth...

Claims

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Application Information

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IPC IPC(8): B24B1/00
CPCC09G1/02H01L21/31053C09K3/1463C09K3/1436
Inventor OTA, RYONAKAKAWAJI, TAKAYUKIASHIZAWA, TORANOSUKEKOYAMA, NAOYUKI
Owner HITACHI CHEM CO LTD
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