US 6,309,966 B1Granted

Apparatus and method of a low pressure, two-step nucleation tungsten deposition

AssigneesMotorola, Inc., White Oak Semiconductor Partnership

InventorsShrinivas Govindarajan, Anthony Ciancio

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Abstract

An apparatus and method of tungsten via fill using a low pressure, 2-step nucleation tungsten deposition process. The tungsten via fill includes a silane soak, a nucleation film growth, and a bulk tungsten film deposition. The nucleation film growth is a low pressure, 2-step process including a controlled first nucleation film growth and a second nucleation film growth. A wafer fabricating system that includes a film depositing system and a control system is used. The film depositing system includes a reaction chamber with at least one silane-containing gas source, a tungsten-containing gas source, and a substrate heating source. The control system instructs the silane-containing gas source and the tungsten-containing gas source to flow with a significantly higher ratio of silane-containing gas (SiH4) to form a first silane-rich nucleation layer. The control system then instructs the gas sources to flow with a higher ratio of tungsten-containing gas, such as WF6, to form a second tungsten nucleation layer. The low pressure, 2-step process results with improved nucleation film step coverage.

Claims10

Dependent claims

A method of depositing a tungsten film to a substrate in a reaction chamber, comprising:

heating the substrate by employing a substrate heating source;
flowing a silane gas mixture until a protective, amorphous silicon layer is formed on a surface of the substrate upon which the tungsten film is to be deposited;
executing a first nucleation film growth by flowing silane gas from a silane-containing gas source at a first flow rate and flowing tungsten gas from a tungsten-containing gas source at a second flow rate, where the first flow rate is greater than the second flow rate, and for a period of time sufficient to provide a first silane-rich nucleation layer;
executing a second nucleation film growth by flowing silane gas from a silane-containing gas source at a first flow rate and flowing tungsten gas from a tungsten-containing gas source at a second flow rate, where the second flow rate is greater than the first flow rate, and for a period of time sufficient to deposit a second tungsten nucleation layer with the desired thickness;
and
flowing a tungsten-rich gas mixture while maintaining a sufficient pressure until a bulk layer of tungsten film is deposited.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/639,183Filed 15 Aug 2000 · us provisional application
Priority: 3 Sep 1999
Granted: 30 Oct 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

H10W 20/045
The barrier, adhesion or liner layers being seed or nucleation layers: for deposition from the gaseous phase, e.g. for chemical vapour deposition…
H10P 14/418
Of conductive or resistive materials: the conductive layers comprising transition metals
H10P 14/43
Using a gas or vapour: chemical deposition, e.g. chemical vapour deposition [CVD]
H10W 20/033
Of conductive barrier, adhesion or liner layers: in openings in dielectrics