Method and apparatus for improving film deposition uniformity on a substrate

Abstract

A method and apparatus for depositing a film on a substrate. According to the present invention a prewafer reaction layer is deposited onto a susceptor placed in the reaction chamber to form a prewafer reaction layer coated susceptor prior to film deposition. A deposition gas is then fed into the reaction chamber so that it flows over the prewafer reaction layer coated susceptor and the substrate to form a film on the prewafer reaction layer coated susceptor and the substrate.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to the field of semiconductor manufacturing, and more specifically to a method and apparatus for uniformly depositing a thin film on a substrate.[0003] 2. Discussion of Related Art[0004] Semiconductor devices are made up of literally millions of discreet devices which are interconnected together to form functional circuits, such as microprocessors, memories and programmable logic devices. In order to improve circuit performance, the fabrication processes generally utilize low resistance metal films such as silicides to form low resistance gate electrodes, contact regions, capacitor electrodes and interconnection lines. Silicide films, such as titanium silicide, can be formed by chemical vapor deposition (CVD) processes.[0005] FIG. 1 is an illustration of a current CVD apparatus which can be used to deposit a titanium silicide film on a semiconductor wafer or substrate. A susceptor 120 divides a chamber 112 into one...

AI Technical Summary

Benefits of technology

[0022] In one embodiment of the present invention a silicide layer is selectively deposited onto silicon containing portions of a substrate. According to the selective silicide deposition process, a susceptor is first coated with a prewafer reaction layer of silicon or a silicide, and then a wafer is placed on the prewafer reaction layer coated susceptor. A deposition gas is then fed into the chamber in such a way that the deposition gas first reacts with the prewafer reaction layer on the susceptor and then reacts with the substrate. In another embodiment of the present invention a silicide layer is blanket deposited over a substrate utilizing an integrated deposition process. According to the integrated deposition process of the present invention, a wafer is placed on a susceptor and then a silicon layer is blanket deposited onto the wafer and onto the susceptor. Deposition gas then fed into the chamber where it initially reacts with the silicon on the susceptor and then reacts with silicon on the wafer. Both techniques are effective at reducing deposition "edge effects" thereby enabling uniform silicide deposition to occur.

Problems solved by technology

A problem with depositing titanium silicide by the process and apparatus described above is that the film deposition rate is non uniform across the surface of the wafer.

Edge effects substantially reduce film thickness uniformity and can make a process entirely unmanufacturable.

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