Chemical Mechanical Planarization for Tungsten-Containing Substrates
AssigneeAir Products and Chemicals, Inc.
InventorsXiaobo Shi, Hongjun Zhou, Blake J. Lew, James Allen Schlueter, Jo-Ann Theresa Schwartz
Life of this patent
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Abstract
Chemical mechanical polishing (CMP) compositions for polishing tungsten or tungsten-containing substrates comprise an abrasive, at least one solid catalyst, a chemical additive selected from the groups consisting of piperazine derivatives, salts of cyanate, and combinations thereof; and a liquid carrier. Systems and processes use the aqueous formulations for polishing tungsten or tungsten-containing substrates.
Claims24
A tungsten chemical mechanical polishing (CMP) composition comprising:
- a) 0.1 wt % to 25 wt % nano-sized abrasive selected from the group consisting of silica, alumina, ceria, titania, zirconia, and combinations thereof;
- b) 0.1 wt % to 0.5 wt % solid catalyst of iron compounds coated particles selected from the group consisting of iron compounds coated colloidal silica, iron compounds coated colloidal or nano-sized inorganic metal oxide particles, and combinations thereof;
- c) 0.0001 w % to 0.5 wt % chemical additive selected from the group consisting of piperazine derivatives, salts of cyanate, and combinations thereof;
- d) 0.5 wt % to 10 wt % oxidizer and
- e) liquid carrier;
- wherein pH of the CMP composition is from about 2.0 to about 8.0.
A process of selective chemical mechanical polishing, comprising steps of:
- a) providing a semiconductor substrate having a surface containing tungsten and at least one other material;
- b) providing a polishing pad;
- c) providing a chemical mechanical polishing (CMP) composition comprising
- 1) 0.1 wt % to 25 wt % nano-sized abrasive selected from the group consisting of silica, alumina, ceria, titania, zirconia, and combinations thereof;
- 2) 0.1 wt % to 0.5 wt % solid catalyst of iron compounds coated particles selected from the group consisting of iron compounds coated colloidal silica, iron compounds coated colloidal or nano-sized inorganic metal oxide particles and combinations thereof;
- 3) 0.0001 wt % to 0.5 wt % chemical additive selected from the groups consisting of piperazine derivatives, salts of cyanate, and combinations thereof;
- 4) 0.5 wt % to 10 wt % oxidizer and
- 5) liquid carrier;
- wherein pH of the CMP composition is from about 2.0 to about 8.0;
- c) contacting the surface of the semiconductor substrate with the polishing pad and the chemical mechanical polishing composition;
- and
- d) polishing the surface of the semiconductor substrate;
- wherein at least a portion of the surface containing tungsten is in contact with both the polishing pad and the chemical mechanical polishing composition;
- and ratio of removal rate of tungsten to removal rate of the at least one other material is equal or greater than 1.
The process of chemical mechanical polishing tungsten containing semiconductor substrate of claim 9, wherein the chemical additive is piperazine derivative having a general molecular structure of:
- wherein R1 and R2 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, aryl, aralkyl, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, substituted organic carboxylic amide, substituted keto, organic carboxylic ester, organic amine, and combinations thereof.
A system of selective chemical mechanical polishing comprising:
- a) a semiconductor substrate having a surface containing tungsten and at least one other material;
- b) a polishing pad;
- c) a chemical mechanical polishing (CMP) composition comprising
- 1) 0.1 wt % to 25 wt % nano-sized abrasive selected from the group consisting of silica, alumina, ceria, titania, zirconia, and combinations thereof;
- 2) 0.1 wt % to 0.5 wt % solid catalyst of iron compounds coated particles selected from the group consisting of iron compounds coated colloidal silica, iron compounds coated colloidal or nano-sized inorganic metal oxide particles and combinations thereof;
- 3) 0.0001 wt % to 0.5 wt % chemical additive selected from the groups consisting of piperazine derivatives, salts of cyanate, and combinations thereof;
- 4) 0.5 wt % to 10 wt % oxidizer and
- 5) liquid carrier;
- wherein pH of the CMP composition is from about 2.0 to about 8.0;
- wherein at least a portion of the surface containing tungsten is in contact with both the polishing pad and the chemical mechanical polishing composition.
The system of selective chemical mechanical polishing of claim 17, wherein
- the chemical additive is piperazine derivative having a general molecular structure of:
- wherein R1 and R2 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, aryl, aralkyl, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, substituted organic carboxylic amide, substituted keto, organic carboxylic ester, organic amine, and combinations thereof.
The system of selective chemical mechanical polishing of claim 17, wherein the piperazine derivative is substituted organic mono-amino piperazine derivative (a) or substituted organic bis-amino piperazine derivative (b) having molecular structures of:
- wherein n is independently selected from 1 to 6:
- and R, R′, R″ and R′″ are independently selected from the group consisting of hydrogen, alkyl, alkoxy, aryl, aralkyl, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, organic carboxylic ester, organic amine, substituted organic carboxylic amide and combinations thereof.
Dependencies are inferred from the claim text.