U.S. patent application number 10/235505 was filed with the patent office on 2003-01-16 for deposition of a siloxane containing polymer.
Invention is credited to Carter, Steven, Shearer, Christine Janet.
Application Number | 20030012877 10/235505 |
Document ID | / |
Family ID | 10825710 |
Filed Date | 2003-01-16 |
United States Patent
Application |
20030012877 |
Kind Code |
A1 |
Carter, Steven ; et
al. |
January 16, 2003 |
Deposition of a siloxane containing polymer
Abstract
An insulating layer is formed onto a surface of a semiconductor
substrate by reacting a silicon-containing compound and a compound
containing peroxide bonding to deposit a short-chain polymer on the
surface of the semiconductor substrate. A deposition rate of the
short-chain polymer is increased by further reacting a substance
which associates readily with the compound containing the peroxide
bonding.
Inventors: |
Carter, Steven; (Gwent,
GB) ; Shearer, Christine Janet; (Bristol,
GB) |
Correspondence
Address: |
VOLENTINE FRANCOS, PLLC
SUITE 150
12200 SUNRISE VALLEY DRIVE
RESTON
VA
20191
US
|
Family ID: |
10825710 |
Appl. No.: |
10/235505 |
Filed: |
September 6, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10235505 |
Sep 6, 2002 |
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09582859 |
Jul 6, 2000 |
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6475564 |
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09582859 |
Jul 6, 2000 |
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PCT/GB99/00191 |
Jan 20, 1999 |
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Current U.S.
Class: |
427/248.1 ;
118/723R; 257/E21.261 |
Current CPC
Class: |
H01L 21/3122 20130101;
C23C 16/401 20130101; H01L 21/02271 20130101; H01L 21/02211
20130101; H01L 21/02126 20130101 |
Class at
Publication: |
427/248.1 ;
118/723.00R |
International
Class: |
C23C 016/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 23, 1998 |
GB |
9801359.2 |
Claims
1. A method of treating a substrate, which method comprises
positioning the substrate in a chamber, introducing into the
chamber in the gaseous or vapour state a silicon-containing
compound, a further compound containing peroxide bonding, and a
substance which associates readily with the compound containing
peroxide bonding, and reacting the silicon-containing compound with
the further compound and the associating substance to provide on
the substrate a an insulating layer.
2. A method according to claim 1, wherein the associating substance
is an oxidising agent.
3. A method according to claim 2, wherein the oxidising agent is
selected from oxygen, ozone, or tetraethoxysilane.
4. A method according to claim 3, wherein the oxidising agent is
oxygen.
5. A method according to any preceding claim, wherein the
silicon-containing compound is an organosilane of the general
formula C.sub.xH.sub.y--Si.sub.nH.sub.a or
(C.sub.xH.sub.y).sub.zSi.sub.nHa.
6. A method according to claim 5, wherein the silicon-containing
compound is of the general formula R--SiH.sub.3.
7. A method according to claim 6 wherein R is a methyl, ethyl,
phenyl or vinyl group.
8. A method according to claim 7, wherein R is a phenyl or methyl
group.
9. A method according to any one of claims 1 to 4, wherein the
silicon-containing compound is a silane or a higher silane.
10. A method according to any preceding claim, wherein the compound
containing peroxide bonding is hydrogen peroxide.
11. A method according to any preceding claim, further comprising
introducing an additional gas into the chamber.
12. A method according to claim 11, wherein the additional gas is
nitrogen.
13. A method according to any preceding claim, wherein the
associating substance is premixed with the compound containing
peroxide bonding or the silicon-containing compound prior to
introduction into the chamber.
14. A method according to any one of claims 1 to 12, wherein the
associating substance is introduced into the chamber as a separate
component.
15. A method according to claim 8, wherein, when R is a methyl
group, the deposition rate is increased to about 1.1 .mu.m/min.
16. A method according to claim 8, wherein, when R is a Phenyl
group, the deposition rate is increased to about 2700
.ANG./min.
17. A method according to claim 9, wherein the deposition rate is
increased to about 1.2 .mu.m/min.
18. A method according to any preceding claim, wherein the flow
rate of the silicon-containing compound into the chamber is between
20 and 145 Sccm.
19. A method according to any preceding claim, wherein the flow
rate of the compound containing peroxide bonding into the chamber
is between 0.2 and 1.0 g/min.
20. A method according to any preceding claim, wherein the flow
rate of the associating substance into the chamber is up to 50
Sccm.
21. A method according to claim 11 or 12, wherein the flow rate of
the additional gas into the chamber is between 50 and 1000
Sccm.
22. A method according to any preceding claim, wherein the pressure
in the chamber is below atmospheric pressure.
23. A method substantially as hereinbefore described, with
reference to, and as illustrated in, the accompanying example and
drawing.
24. An apparatus for implementing the method of any preceding
claim, including means for introducing the components into the
chamber and platen means for supporting the semiconductor
substrate.
25. An apparatus according to claim 24, comprising a CVD and/or a
PECVD chamber.
26. An apparatus substantially as hereinbefore described with
reference to, and as illustrated in, the accompanying drawing.
Description
[0001] This invention relates to a method and apparatus for
treating a substrate, such as a semiconductor wafer and, in
particular, but not exclusively, to a method and apparatus for
providing an increase in deposition rate of a high grade insulation
layer. In addition, a low dielectric constant (known as low k) may
also be provided by the method and apparatus of the present
invention.
[0002] In the earlier Patent Application WO94/01885, the contents
of which are incorporated herein by reference, a planarisation
technique is described in which a liquid short-chain polymer is
formed on a semiconductor wafer by reacting silane (SiH.sub.4) or a
higher silane with hydrogen peroxide (H.sub.2O.sub.2). In addition,
the earlier co-pending Patent Application PCT/GB97/02240 discloses
a method and apparatus for providing a low dielectric constant in a
planarisation operation. The method disclosed utilises an
organosilane compound and a compound containing peroxide bonding to
provide a short-chain polymer as a deposition layer on a
semiconductor substrate. It has been found that the reactants used
in prior art processes provide very low deposition rates of the
resulting polymer layer on the semiconductor substrate. For
example, investigations into the reaction of phenylsilane and
H.sub.2O.sub.2 yielded low deposition rates of the order of 600
.ANG./min.
[0003] The main purpose of the present invention is to put down a
high grade insulation layer as rapidly as possible, preferably
without having a detrimental effect on the low dielectric constant
of the insulator, and even improving the dielectric constant.
[0004] We have found that it is possible to increase significantly
the deposition rates whilst maintaining other desirable properties,
including a low dielectric constant, thereby improving the overall
process of the deposition.
[0005] According to a first aspect of the present invention there
is provided a method of treating a substrate, which method
comprises positioning the substrate in a chamber, introducing into
the chamber in the gaseous or vapour state a silicon-containing
compound, a further compound containing peroxide bonding, and a
substance which associates readily with the compound containing
peroxide bonding, and reacting the silicon-containing compound with
the further compound and the associating substance to orovide on
the substrate an insulating layer.
[0006] Whilst the applicant is not to be restricted hereby, it is
thought that the associating substance promotes the initiation
between the compound containing peroxide bonding and the
silicon-containing compound. Thus, the further compound, and the
associating substance react with each other in the formation of the
insulating layer.
[0007] The substance which associates readily with the compound
containing peroxide bonding is preferably an oxidising agent, for
example oxygen, ozone or tetraethoxysilane (TEOS). However, any
material soluble in the compound containing peroxide bonding is
appropriate, for example carbon monoxide or carbon dioxide. The
most preferred oxidising agent is oxygen.
[0008] The reaction which occurs is a chemical vapour deposition
process and does not require an additional plasma, although such a
plasma (for example a weakly ionised plasma) may, if required, be
used within the process chamber. Thus, the reactants are preferably
capable of reacting spontaneously. The reaction is thought to be a
surface reaction.
[0009] The silicon-containing compound may be an organosilane, for
example one of the general formula C.sub.xH.sub.y--Si.sub.nH.sub.a,
or one of the general formula
(C.sub.xH.sub.y).sub.zSi.sub.nH.sub.a, where x, y, z, n and a are
any suitable values, for example integers. The silicon containing
compound is preferably of the general formula R--SiH.sub.3.
Preferably, R is a methyl, ethyl, phenyl, or vinyl group and it is
particularly preferred that R is a phenyl or methyl group.
Alternatively, the silicon-containing compound may be a silane (for
example silane itself) or a higher silane. A further alternative is
dimethylsilane. The silicon-containing compound is preferably not
TEOS or other organometallic compound.
[0010] Any suitable combination of the components may be used but
as will be understood by those skilled in the art certain
combinations and pressures may not be appropriate as they are
explosive in the chamber.
[0011] The compound containing peroxide bonding is preferably
hydrogen peroxide.
[0012] In an alternative embodiment, the method may further
comprise the step of introducing an additional gas, for example
nitrogen, into the chamber.
[0013] The associating substance can be introduced in any way.
Thus, the associating substance may be pre-mixed with the compound
containing peroxide bonding or the silicon-containing compound
prior to introduction into the chamber, although it has been
observed that the deposition rate is particularly increased if the
associating substance is pre-mixed with the compound containing
peroxide bonding. Alternatively, the associating substance may be
introduced into the chamber as a separate component.
[0014] When R is a methyl group, eg. when methyl silane is the
silicon-containing compound, the deposition rate is increased to
about 1.1 .mu.m/min. Thus when oxygen is used as the associating
substance the deposition rate was increased from about 8000
.ANG./min which was the rate in the case in which no oxygen was
used. When R is a phenyl group the deposition rate is increased
from about 600 .ANG./min to 2700 .ANG./min. Furthermore, when
oxygen is used as the associating substance, the deposition rate
when a silane or higher silane is used is increased from about 9000
.ANG./min to about 1.2 .mu.m/min. In addition, it has been found
that the addition of the associating substance, in particular
oxygen, leads to a slight reduction in the dielectric constant of
the film formed on the substrate, typically from 3.2 to 2.8.
[0015] A particularly preferred flow rate of the silicon-containing
compound into the chamber is between 20 and 145 Sccm
(3.4.times.10.sup.-2 to 0.24 Pa.m.sup.3/s), even more preferably
about 45 Sccm (7.6.times.10.sup.-2Pa.m .sup.3/s). The flow rate of
the compound containing peroxide bonding into the chamber is
preferably between 0.2 and 1.0 g/min and is even more preferably
about 0.22 g/min. The flow rate of the associating substance into
the chamber is preferably up to 50 Sccm (8.4.times.10.sup.-2
Pa.m.sup.3/s) and even more preferably is about 10 Sccm
(1.7.times.10.sup.-2 Pa.m3/s). Above 20 Sccm spontaneous momentary
pressure bursts are observed indicating vigorous reactions and
rates above 50 Sccm may well therefore be unsafe in practice.
Whilst any suitable pressure in the chamber can be used, it has
been found that appropriate pressures are below atmospheric
pressure, for example in the range of 200 to 5000 mT, preferably
about 1000 mT. When an further gas is used, its flow rate into the
chamber is preferably between 50 and 1000 Sccm (8.4.times.10.sup.-2
to 1.7 Pa.m.sup.3/s), even more preferably about 80 Sccm (0.14
Pa.m.sup.3/s). The units Sccm (Standard Cubic Centimeters per
Minute) are at standard temperature and pressure.
[0016] The method may, if required, comprise the further step of
removing water and/or OH from the layer formed from the short-chain
polymer. Furthermore, the method may further comprise the step of
forming or depositing an underlayer or a base layer prior to the
deposition of the polymer layer. The method may further comprise
the step of depositing or forming a capping layer on the surface of
the formed layer and this layer is preferably applied in a PECVD
process.
[0017] According to a second aspect of the present invention there
is provided an apparatus for implementing the above method which
comprises means for introducing the components into the chamber and
platen means for supporting the substrate. The apparatus may
comprise a Chemical Vapour Deposition (CVD) or Plasma Enhanced
Vapour Deposition process (PECVD) chamber.
[0018] Whilst the invention has been described above, it extends to
any inventive combination of the features set out above or in the
following description.
[0019] The invention will now be described, by way of example, with
reference to the following example and the following drawing, and
in which:
[0020] FIG. 1 is a schematic view of an apparatus for performing
the treatment method.
[0021] Referring to FIG. 1, an apparatus for treating semiconductor
wafers, or the like, is schematically illustrated at 1. The general
construction of such an apparatus is well known in the art and
therefore only the features which are relevant for the
understanding of the invention are described. Thus, the apparatus 1
includes a chamber 2 having a duplex shower head 3 and a wafer
support 4. The shower head 3 is connected to RF source 6 to form
one electrode while the support 4 is earthed and forms another
electrode. Alternatively, the RF source 6 could be connected to the
support 4 and the shower head 3 earthed. The shower head 3 is
connected by respective pipes 7 and 8 to a source of O.sub.2 and
H.sub.2O.sub.2 on the one hand and phenylsilane (C.sub.6H.sub.8Si)
on the other hand.
[0022] In use, the apparatus is arranged to deposit a short chain
polymer on a semiconductor wafer or other substance This may also
provide planarisation either locally or globally, or "gap filling".
The polymer is formed by introducing the components into the
chamber, together with a carrier gas, for example nitrogen, if
required, and reacting them within the chamber. The reaction may
occur spontaneously or may require initiation, for example from an
external energy source. The nitrogen may be needed to improve the
process due to the small flow rates of the other components, and it
may form part of the process. The flow of the reactants is
maintained at a desired level and they are removed from the chamber
via outlet 9. The resultant polymer is deposited on the wafer. As
regards the mechanism involving oxygen, whilst the applicant is not
to be restricted hereby, it is believed that the O.sub.2 is being
associated with the H.sub.2O.sub.2 promoting the reaction between
H.sub.2O.sub.2 and C.sub.6H.sub.8Si. The reaction may take place at
the wafer surface.
EXAMPLE
[0023] Investigations into the reaction of phenylsilane
(C.sub.6H.sub.8Si) and H.sub.2O.sub.2 yielded very low deposition
rates (of the order of 600 .ANG./min). In order to promote the
reaction, a small amount of additional oxidant --O.sub.2-- was
added to the process which proved successful in increasing the
deposition rate to in excess of 2700 .ANG./min.
[0024] The process used for the investigations was:
1 preferred process range investigated C.sub.6H.sub.8Si (Sccm) 45
20 .fwdarw. 145 H.sub.2O.sub.2 (g/min) 0.22 0.2 .fwdarw. 1.0
N.sub.2 (Sccm) 80 50 .fwdarw. 1000 O.sub.2 (Sccm) 10 0 .fwdarw. 50
Pressure (mT) 1000 200 .fwdarw. 5000
[0025] As has already been mentioned it was found that, when the
rate of O.sub.2 flow is increased above 20 Sccm, an increasingly
vigorous reaction occurred causing large fluctuations in chamber
pressure.
[0026] Furthermore, the addition of O.sub.2 has been found to
increase the deposition rate of a process in which the silicon
containing compound as a silane or higher silane from about 9000
.ANG./min to about 1.2 .mu.m/min, and of a process in which
MeSiH.sub.3 is used from approximately 8000 .ANG./min to about 1.1
.mu.m/min.
* * * * *