Patent US6653234B2 successfully refreshed from Google Patents.
US6653234B2
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Chemical vapor deposition of titanium from titanium tetrachloride and hydrocarbon reactants
Assignee: Mosaid Technologies Inc
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Filing: 2001-12-07
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Granted: 2003-11-25
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Expires: 2021-12-07
Abstract
Abstract A new process for depositing titanium metal layers via chemical vapor deposition is disclosed. The process provides deposited titanium layers having a high degree of conformality, even in trenches and contact openings having aspect ratios greater than 1:5. The reaction gases for the improved process are titanium tetrachloride and a hydrocarbon gas, which for a preferred embodiment of the process is methane. The reaction is carried out in a plasma environment created by a radio frequency source greater than 10 KHz. The key to obtaining titanium metal as a reaction product, rather than titanium carbide, is to set the plasma-sustaining electrical power within a range that will remove just one hydrogen atom from each molecule of the hydrocarbon gas. In a preferred embodiment of the process, highly reactive methyl radicals (CH3-) are formed from methane gas. These radicals attack the titanium-chlorine bonds of the tetrachloride molecule and form chloromethane, which is evacuated from the chamber as it is formed. Titanium metal deposits on a wafer or other substrate that has been heated to a temperature within a preferred range of 200-500° C.
Inventors
- 👤 Ravi Iyer
- 👤 Sujit Sharan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:33
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/06; C23C16/08; H; H10; H10P; H10P14/00; H10P14/40; H10P14/418; H10P14/42; H10P14/43; Y; Y10; Y10S; Y10S438/00; Y10S438/909
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
131 words
A chemical vapor deposition process using a plasma in a deposition chamber having a heater for depositing a metal layer on a substrate in said deposition chamber, comprising: admitting a hydrocarbon gas into said deposition chamber; admitting titanium tetrachloride gas into said deposition chamber; forming a plasma in said deposition chamber having a power level greater than a first ionization energy, but less than a second ionization energy, of said at least one hydrocarbon gas for forming hydrocarbon radicals therein, said at least one hydrocarbon gas comprising an alkane; and heating said substrate to a temperature sufficient for said radicals formed from said at least one hydrocarbon gas to react with chlorine atoms from said titanium tetrachloride gas for depositing a layer of titanium metal on a surface of said substrate.
Claim 2
Dependent Claim
131 words
A chemical vapor deposition process using a plasma in a deposition chamber having a heater for depositing a metal layer on a substrate in said deposition chamber, comprising: admitting a hydrocarbon gas into said deposition chamber; admitting titanium tetrachloride gas into said deposition chamber; forming a plasma in said deposition chamber having a power level greater than a first ionization energy, but less than a second ionization energy, of said at least one hydrocarbon gas for forming hydrocarbon radicals therein, said at least one hydrocarbon gas comprising an alkane; and heating said substrate to a temperature sufficient for said radicals formed from said at least one hydrocarbon gas to react with chlorine atoms from said titanium tetrachloride gas for depositing a layer of titanium metal on a surface of said substrate.
Claim 3
Dependent Claim
20 words
The process of claim 1 , wherein said substrate is heated to a temperature within a range of 200-500° C.
Claim 4
Dependent Claim
37 words
The process of claim 1 , wherein said at least one hydrocarbon gas is selected from a group consisting of compounds C n H 2n+2 , C n H 2n , and C n H 2n−2 .
Claim 5
Dependent Claim
24 words
The process of claim 1 , wherein said at least one hydrocarbon gas is an alkane having fewer than five carbon atoms per molecule.
Claim 6
Dependent Claim
15 words
The process of claim 4 , wherein said at least one hydrocarbon gas is methane.
Claim 7
Dependent Claim
24 words
The process of claim 1 , further comprising: mounting said substrate on a susceptor; heating said susceptor; and heating said substrate using said susceptor.
Claim 8
Dependent Claim
26 words
The process of claim 1 , wherein said titanium tetrachloride is mixed with a carrier gas selected from a group consisting of helium, argon and hydrogen.
Claim 9
Dependent Claim
20 words
The process of claim 7 , wherein the titanium tetrachloride is introduced into said carrier gas in a bubbler apparatus.
Claim 10
Dependent Claim
19 words
The process of claim 7 , wherein a liquid injector sprays said titanium tetrachloride and passes through a vaporizer.
Claim 11
Dependent Claim
28 words
The process of claim 1 , wherein said at least one hydrocarbon gas is mixed with a carrier gas selected from a group consisting of helium and argon.
Claim 12
Dependent Claim
20 words
The process of claim 1 , wherein nondepositing reaction products are removed from said deposition chamber as said process proceeds.
Claim 13
Dependent Claim
16 words
The process of claim 11 , wherein an alkyl chloride gas is a principal reaction product.
Claim 14
Dependent Claim
41 words
The process of claim 1 , wherein said deposition chamber is a cold wall deposition chamber, walls of which are maintained at a temperature within a preferred range of 100-200° C. in order to prevent condensation of said titanium tetrachloride thereon.
Claim 15
Dependent Claim
16 words
The process of claim 1 , wherein said deposition chamber is a hot wall deposition chamber.
Claim 16
Dependent Claim
16 words
The process of claim 1 , wherein said plasma is produced with a radio frequency source.
Claim 17
Dependent Claim
24 words
The process of claim 15 , wherein said radio frequency source operates at a power setting within a range of 20 to 100 watts.
Claim 18
Dependent Claim
19 words
The process of claim 15 , wherein said radio frequency source operates at a frequency greater than 10 KHz.
Claim 19
Dependent Claim
23 words
The process of claim 1 , wherein said deposition chamber is maintained at a pressure within a range of 2 to 100 torr.
Claim 20
Dependent Claim
24 words
The process of claim 1 , wherein said deposition chamber is maintained at a pressure within a preferred range of 2 to 5 torr.
Claim 21
Dependent Claim
26 words
The process of claim 1 , wherein said titanium tetrachloride and the at least one hydrocarbon gas are premixed before being admitted to said deposition chamber.
Claim 22
Dependent Claim
31 words
The process of claim 20 , wherein a ratio of said at least one hydrocarbon gas to said titanium tetrachloride in said premixture is between four and one thousand to one.
Claim 23
Dependent Claim
13 words
The process of claim 1 , wherein said substrate is a semiconductor wafer.
Claim 24
Dependent Claim
146 words
A chemical vapor deposition process using a plasma in a deposition chamber having a heater for depositing a metal layer on a semiconductor wafer comprising: admitting at least one hydrocarbon gas into said deposition chamber; admitting titanium tetrachloride gas into said deposition chamber; forming a plasma within said plasma-enhanced deposition chamber of the at least one hydrocarbon gas for forming hydrocarbon radicals, said at least one hydrocarbon gas comprising an alkane; maintaining said plasma at a power level greater than a first ionization energy, but less than a second ionization energy, of said at least one hydrocarbon gas, for forming said hydrocarbon radicals; and heating said semiconductor wafer to a temperature sufficient to induce said hydrocarbon radicals to react with chlorine atoms from said titanium tetrachloride gas for forming chlorinated hydrocarbon molecules for depositing a layer of titanium metal on a surface of said semiconductor wafer.
Claim 25
Dependent Claim
146 words
A chemical vapor deposition process using a plasma in a deposition chamber having a heater for depositing a metal layer on a semiconductor wafer comprising: admitting at least one hydrocarbon gas into said deposition chamber; admitting titanium tetrachloride gas into said deposition chamber; forming a plasma within said plasma-enhanced deposition chamber of the at least one hydrocarbon gas for forming hydrocarbon radicals, said at least one hydrocarbon gas comprising an alkane; maintaining said plasma at a power level greater than a first ionization energy, but less than a second ionization energy, of said at least one hydrocarbon gas, for forming said hydrocarbon radicals; and heating said semiconductor wafer to a temperature sufficient to induce said hydrocarbon radicals to react with chlorine atoms from said titanium tetrachloride gas for forming chlorinated hydrocarbon molecules for depositing a layer of titanium metal on a surface of said semiconductor wafer.
Claim 26
Dependent Claim
23 words
The process of claim 23 , wherein said deposition chamber is maintained at a pressure within a range of 2 to 10 torr.
Claim 27
Dependent Claim
36 words
The process of claim 23 , wherein said power level comprises a radio frequency source operating at a power setting within a range of 20 to 100 watts and at a frequency greater than 10 KHz.
Claim 28
Dependent Claim
48 words
The process of claim 23 , wherein said titanium tetrachloride and said at least one hydrocarbon gas are premixed prior to their admission to said deposition chamber, having a ratio of methane gas to said titanium tetrachloride in said premixture being between four and one thousand to one.
Claim 29
Dependent Claim
15 words
The process of claim 23 , wherein said at least one hydrocarbon gas is methane.
Claim 30
Dependent Claim
36 words
The process of claim 23 , wherein said at least one hydrocarbon gas is selected from a group consisting of compounds C n H 2n+2 , C n H 2n and C n H 2n−2 .
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