Hydrogen assisted undoped silicon oxide deposition process...

Details Hydrogen assisted undoped silicon oxide deposition process... Hydrogen assisted undoped silicon oxide deposition process...

2001-05-11

2003-07-22

Cuneo, Kamand (Department: 2829)

Semiconductor device manufacturing: process

Coating of substrate containing semiconductor region or of...

Insulative material deposited upon semiconductive substrate

C438S149000, C438S758000, C438S773000, C438S778000

Reexamination Certificate

active

06596653

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to the manufacture of integrated circuits. More specifically, the invention relates to an improved method of depositing silicon oxide layers for use as insulation layers in such integrated circuits.
One of the primary steps in the fabrication of modern semiconductor devices is the formation of a film, such as a silicon oxide, on a semiconductor substrate. Silicon oxide is widely used as an insulating layer in the manufacture of semiconductor devices. As is well known, a silicon oxide film can be deposited by thermal chemical vapor deposition (CVD) or a plasma-enhanced chemical vapor deposition (PECVD) processes. In a conventional thermal CVD process, reactive gases are supplied to the substrate surface where heat-induced chemical reactions (homogeneous or heterogeneous) take place to produce a desired film. In a conventional plasma process, a controlled plasma is formed to decompose and/or energize reactive species to produce the desired film.
Semiconductor device geometries have dramatically decreased in size since such devices were first introduced several decades ago. Smaller feature sizes have resulted in the presence of increased aspect ratio gaps for some applications, for example, between adjacent conductive lines or in etched trenches. The aspect ratio of a gap is defined by the ratio of the gap's height or depth to its width. These spaces are difficult to fill using conventional CVD methods. A film's ability to completely fill such gaps is referred to as the film's “gap-filling” ability. Silicon oxide is one type of insulation film that is commonly used to fill the gaps in intermetal dielectric (IMD) applications, premetal dielectric (PMD) applications and shallow trench isolation (STI) applications among others. Such a silicon oxide film is often referred to as a gap-fill film or a gap-fill layer.
Some integrated circuit manufacturers have turned to the use of high density plasma CVD (HDP-CVD) systems to deposit silicon oxide gap-fill layers. HDP-CVD systems form a plasma that is approximately two orders of magnitude or greater than the density of a standard, capacitively-coupled plasma CVD system. Examples of HDP-CVD systems include inductively-coupled plasma systems and electron cyclotron resonance (ECR) plasma systems among others. HDP-CVD systems generally operate at lower pressure ranges than low density plasma systems. The low chamber pressure employed in HDP-CVD systems provides active species having a long mean-free-path and reduced angular distribution. These factors, in combination with the plasma's density, contribute to a significant number of constituents from the plasma reaching even the deepest portions of closely spaced gaps, providing a film with improved gap-fill capabilities as compared to films deposited in a low density plasma CVD system.
Another factor that allows films deposited by HDP-CVD techniques to have improved gap-fill characteristics as compared to films deposited by other CVD techniques is the occurrence of sputtering, promoted by the plasma's high density, simultaneous with film deposition. The sputtering element of HDP deposition slows deposition on certain features, such as the comers of raised surfaces, thereby contributing to the increased gap-fill ability of HDP deposited films. Some HDP-CVD systems introduce argon or a similar heavy inert gas to further promote the sputtering effect. These HDP-CVD systems typically employ an electrode within the substrate support pedestal that enables the creation of an electric field to bias the plasma toward the substrate. The electric field can be applied throughout the HDP deposition process to further promote sputtering and provide better gap-fill characteristics for a given film.
One HDP-CVD process commonly used to deposit a silicon oxide film forms a plasma from a process gas that includes silane (SiH
4
), molecular oxygen (O
2
) and argon (Ar). This silicon oxide film has improved gap-fill characteristics as opposed to some silicon oxide films deposited by other non-HDP-CVD plasma techniques and is useful for a variety of applications. Despite the improvement in gap-fill capability provided by HDP-CVD systems and the relatively good gap-fill characteristics of HDP-CVD silicon oxide films in particular, the development of film deposition techniques that enable the deposition of silicon oxide layers having even further improved gap-fill characteristics are desirable. Such improved silicon oxide film deposition are particularly desirable in light of the aggressive gap-fill challenges presented by integrated circuit designs employing minimum feature sizes of 0.18 microns and less.
SUMMARY OF THE INVENTION
Embodiments of the present invention pertain to an improved method of depositing silicon oxide films using HDP-CVD deposition techniques. These embodiments enable improved gap-fill capabilities as compared to HDP-CVD silicon oxide deposition techniques that do not employ the method of the present invention and the embodiments are useful for the manufacture of integrated circuits having minimum feature sizes of 0.18 microns or less.
In one embodiment, the present invention forms an undoped silicon oxide layer (USG) over a substrate disposed in a high density plasma substrate processing chamber. The silicon oxide layer is formed by flowing a process gas into the substrate processing chamber and forming a high density plasma (i.e., a plasma having an ion density of at least 1×10
11
ions/cm
3
) from the process gas to deposit said silicon oxide layer over said substrate. The process gas includes a silane gas, an oxygen-containing source, an inert gas and a hydrogen-containing source that is selected from the group of H
2
, H
2
O, NH
3
, CH
4
, C
2
H
6
, or a hydride gas that does not include silicon, boron or phosphorus. The deposited silicon oxide layer has a hydrogen content of less than or equal to 2 atomic percent.
In another embodiment, the present invention forms an undoped silicon oxide layer (USG) from a process gas consisting of SiH
4
, O
2
, Ar and H
2
. The flow rate ratio of O
2
to the combined flow of SiH
4
and H
2
in the process gas is between 1.6-2.5:1 inclusive and the flow rate ratio of H
2
to SiH
4
is between 0.5-2.0:1 inclusive. The process gas is flowed into the substrate processing chamber and a high density plasma is formed from the process gas to deposit the silicon oxide layer over the substrate. The deposited silicon oxide layer has a dielectric constant of between 4.0 and 4.2 and contains less than or equal to 2 atomic percent hydrogen.
These and other embodiments of the present invention, as well as its advantages and features are described in more detail in conjunction with the text below and attached figures.


REFERENCES:
patent: 4690746 (1987-09-01), McInerney et al.
patent: 4737379 (1988-04-01), Hudgens et al.
patent: 4835005 (1989-05-01), Hirooka et al.
patent: 4890575 (1990-01-01), Ito et al.
patent: 5645645 (1997-07-01), Zhang et al.
patent: 5712185 (1998-01-01), Tsai et al.
patent: 5719085 (1998-02-01), Moon et al.
patent: 5804259 (1998-09-01), Robles
patent: 5872058 (1999-02-01), Van Cleemput et al.
patent: 5910342 (1999-06-01), Hirooka et al.
patent: 5976327 (1999-11-01), Tanaka
patent: 5990013 (1999-11-01), Berenguer et al.
patent: 6013191 (2000-01-01), Nasser-Faili et al.
patent: 6013584 (2000-01-01), M'Saad
patent: 6030881 (2000-02-01), Papasouliotis et al.
patent: 6039851 (2000-03-01), Iyer
patent: 6194038 (2001-02-01), Rossman
patent: 6217658 (2001-04-01), Orczyk et al.
patent: 6228751 (2001-05-01), Yamazaki et al.
patent: 6313010 (2001-11-01), Nag et al.
patent: 6395150 (2002-05-01), Van Cleemput et al.
patent: 2 267 291 (1993-12-01), None
patent: 2-58836 (1990-02-01), None
patent: 7-161703 (1995-06-01), None
“Handbook of Low and High Dielectric Constant Materials and Their applications”, Nalwa, vol. 1, 1999, p66.*
V.Y. Vassiliev et al., “Trends in Void-Free Pre-Metal CVD Dielectrics,”Solid State Technology, pp. 129-136 (Mar. 2001).
Nalwa, H.S.,Handbo

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