Method for removal of impurities in cyclic siloxanes useful as precursors for low dielectric constant thin films
AssigneeAdvanced Technology Materials, Inc.
InventorsChongying Xu, Thomas H. Baum, Alexander S. Borovik, Ziyun Wang, James T.Y. Lin, Scott Battle, Ravi K. Laxman
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Abstract
A process for reducing the level(s) of water and/or other impurities from cyclosiloxanes by either azeotropic distillation, or by contacting the cyclosiloxane compositions with an adsorbent bed material. The purified cyclosiloxane material is useful for forming low-dielectric constant thin films having dielectric constants of less than 3.0, more preferably 2.8 to 2.0.
Claims46
A process for reducing the concentration of water and optionally at least one impurity, from a cyclosiloxane precursor, wherein said process is selected from the group consisting of:
- (1) contacting the cyclosiloxane precursor with an adsorbent bed material, so as to remove therefrom at least a portion of the water, and optionally at least one other impurity, to produce a cyclosiloxane precursor having a reduced level of water and optionally impurity;
- and removing the purified cyclosiloxane precursor from the adsorbent bed material;
- and
- (2) distilling a starting mixture comprising at least water and at least one [SiO]n cyclosiloxane CVD precursor, in the presence of an azeotropic component, so as to form an azeotropic mixture with the water contained in said starting mixture;
- in order to produce (A) a distillate fraction comprising water and the azeotropic component and (B) a balance fraction comprising a purified cyclosiloxane precursor, whereby said balance fraction (B) is substantially reduced in water relative to said starting mixture;
- and
- (3) a combination of 1 and 2.
A CVD method of depositing a low dielectric constant thin film on a substrate from a [SiO]n cyclosiloxane precursor that has been purified by a method selected from the group consisting of:
- (1) contacting the cyclosiloxane precursor comprising water and optionally at least one impurity with an adsorbent bed material, so as to remove therefrom at least a portion of the water and optionally at least a portion of the impurity, to produce a purified cyclosiloxane precursor having a reduced level of water and optionally at least one impurity;
- and removing the purified cyclosiloxane precursor from the adsorbent bed;
- and
- (2) distilling a starting mixture comprising at least water and at least one [SiO]n cyclosiloxane CVD precursor, in the presence of an azeotropic component, so as to form an azeotropic mixture with the water contained in said starting mixture;
- in order to produce (A) a distillate fraction comprising water and the azeotropic component and (B) a balance fraction comprising purified cyclosiloxane precursor, whereby said balance fraction (B) is substantially reduced in water relative to the starting mixture;
- and
- (3) a combination of 1 and 2.
1,3,5,7-tetramethylcyclotetrasiloxane purified by a process selected from the group consisting of:
- (1) contacting the cyclosiloxane precursor with an adsorbent bed material, so as to remove therefrom at least a portion of the water, and optionally at least one impurity, selected from the group consisting of acidic and basic impurities, to produce a cyclosiloxane precursor having a reduced level of water and optionally at least one impurity;
- and removing the purified cyclosiloxane precursor from the adsorbent bed material;
- and
- (2) distilling a starting mixture comprising at least water and at least one [SiO]n cyclosiloxane CVD precursor, in the presence of an azeotropic component, so as to form an azeotropic mixture with the water contained in said starting mixture;
- in order to produce (A) a distillate fraction comprising water and the azeotropic component and (B) a balance fraction comprising a purified cyclosiloxane precursor, whereby said balance fraction (B) is substantially reduced in water relative to said starting mixture;
- and
- (3) a combination of 1 and 2.
A SiCOH low dielectric constant thin film deposited from 1,3,5,7-tetramethylcyclotetrasiloxane purified by a method selected from the group consisting of:
- (1) contacting the cyclosiloxane precursor with an adsorbent bed material, so as to remove therefrom at least a portion of the water, and optionally at least impurity, selected from the group consisting of acidic and basic impurities, to produce a cyclosiloxane precursor having a reduced level of water and optionally acidic impurity;
- and removing the purified cyclosiloxane precursor from the adsorbent bed material;
- and
- (2) distilling a starting mixture comprising at least water and at least one [SiO]n cyclosiloxane CVD precursor, in the presence of an azeotropic component, so as to form an azeotropic mixture with the water contained in said starting mixture;
- in order to produce (A) a distillate fraction comprising water and the azeotropic component and (B) a balance fraction comprising a purified cyclosiloxane precursor, whereby said balance fraction (B) is substantially reduced in water relative to said starting mixture;
- and
- (3) a combination of 1 and 2.
Dependencies are inferred from the claim text.