Forming metal silicide resistant to subsequent thermal processing
AssigneeMicron Technology, Inc.
InventorsRobert Burke, Farrell Good, Anand Srinivasan
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Abstract
A metal suicide film and method of forming the same are provided. The method comprises depositing metal silicide layers onto a substrate assembly with alternating layers of silicon. The resulting metal silicide film has a disrupted grain structure and smaller grain sizes than prior art films of the same thickness, which increases the resistance of the material to stress cracks in subsequent thermal processing and reduces the overall residual stress of the material.
Claims53
A method of forming an electrically conductive film, comprising:
- forming a metal silicide layer over a substrate assembly;
- forming a silicon layer having a thickness of less than about 10 Å over the metal silicide layer;
- forming a metal silicide layer over the silicon layer;
- and
- sequentially repeating the step of forming a silicon layer having a thickness of less than about 10 Å and the step of forming a metal silicide layer over the silicon layer n times, where n is an integer of 0 or greater, until a film of desired thickness t is formed.
A method of forming a tungsten silicide film by chemical vapor deposition (CVD), comprising:
- introducing a silicon gas flow into a CVD chamber;
- introducing a tungsten gas flow into the chamber which reacts with the silicon gas flow to form a layer of tungsten silicide;
- shutting off the tungsten gas flow from the chamber while maintaining the silicon gas flow into the chamber to form a silicon layer having a thickness less than about 10 Å;
- reintroducing the tungsten gas flow into the chamber after the step of shutting off, wherein the tungsten gas flow reacts with the silicon gas flow to form an additional layer of tungsten silicide;
- and
- sequentially repeating the steps of shutting off and reintroducing the tungsten gas flow n times, where n is an integer of 0 or greater.
A method of forming an electrically conductive runner or wiring in a semiconductor device, comprising:
- maintaining a silicon gas flow into a CVD chamber;
- and
- intermittently pulsing on and off a metal gas flow into the chamber to form a plurality of distinct metal silicide layers, said plurality of distinct metal silicide layers together forming a single electrically conductive film.
A method of forming an electrically conductive film, comprising:
- forming a plurality of layers of metal silicide over a substrate assembly;
- forming an interrupting layer between each layer of metal silicide;
- and
- at least partially diffusing at least one layer of metal silicide and the interrupting layer into each other to form a single electrically conductive film.
A method of forming a single electrically conductive film, comprising:
- forming a first silicide layer of a first thickness on a substrate so that the maximum vertical grain size is limited to the first thickness;
- interrupting the vertical grain growth of the first silicide layer by forming an interrupting layer on an exposed surface of the first silicide layer;
- and
- forming a second silicide layer on an exposed surface of the interrupting layer, wherein the step of interrupting the vertical grain growth in the first layer results in the electrically conductive film having reduced residual stress, wherein at least the first and second metal silicide layer together with the interrupting layer form a single electrically conductive film.
A method of forming a metal silicide film, comprising:
- forming a plurality of metal silicide layers;
- forming at least one layer of silicon alternating between the plurality of metal silicide layers, each layer of silicon being no more than about one to two monolayers thick;
- and
- at least partially diffusing the layers of metal silicide and silicon into each other to form a single electrically conductive film.
A method of forming an electrically conductive film of total thickness t, comprising:
- forming a plurality of metal silicide sub-layers one over another and separated by no more than about 10 Å, each of the sub-layers including a plurality of grains, the grain structure of each layer being disrupted from the grain structure of an adjacent layer;
- wherein the average vertical grain size in each of the metal silicide sub-layers is less than about the total thickness t of the film divided by the number of metal silicide sub-layers, and the plurality of metal silicide sub-layers together form a single electrically conductive film.
A method of forming metal silicide film, comprising:
- forming a plurality of metal silicide layers, wherein the growth of each of said layers is interrupted so as to disrupt the grain structure of each of the layers between layers such that when the metal silicide film has a total thickness t, the average grain size in each of the metal silicide layers is less than t divided by the total number of metal silicide layers;
- wherein the plurality of metal silicide layers together form a single electrically conductive film.
Dependencies are inferred from the claim text.