Chemical vapor deposition of a thin film onto a substrate

• US 5,856,240 A
• Filed: 11/21/1994
• Issued: 01/05/1999
• Est. Priority Date: 04/05/1993
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Chang, Mei, Littau, Karl A., Sinha, Ashok, Lei, Lawrence Chung-Lai, Perlov, Ilya, Morrison, Alan F.
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): NGUYEN, THANH T
• Application Number:
  US08/342,522
• Time in Patent Office: 1,506 Days
• Field of Search: 437/225, 437/245, 427/314, 438/778, 438/935, 438/680, 438/681, 438/758
• US Class Current: 438/758
• CPC Class Codes: C23C 16/4412 Details relating to the exhausts, e.g. pumps, filters, scrubbers, particle traps
• CPC Class Codes: C23C 16/45519 Inert gas curtains
• CPC Class Codes: C23C 16/45521 the gas, other than thermal contact gas, being introduced the rear of the substrate to flow around its periphery
• CPC Class Codes: C23C 16/458 characterised by the method used for supporting substrates in the reaction chamber
• CPC Class Codes: C23C 16/4583 the substrate being supported substantially horizontally
• CPC Class Codes: C23C 16/4585 Devices at or outside the perimeter of the substrate support, e.g. clamping rings, shrouds
• CPC Class Codes: C23C 16/46 characterised by the method used for heating the substrate C23C16/48, C23C16/50 take precedence
• CPC Class Codes: H01L 21/67103 mainly by conduction
• CPC Class Codes: H01L 21/68 for positioning, orientation or alignment
• CPC Class Codes: H01L 21/68721 characterised by edge clamping, e.g. clamping ring
• CPC Class Codes: H01L 21/68728 characterised by a plurality of separate clamping members, e.g. clamping fingers
• CPC Class Codes: H01L 21/68735 characterised by edge profile or support profile
• CPC Class Codes: H01L 21/6875 characterised by a plurality of individual support members, e.g. support posts or protrusions
• CPC Class Codes: H01L 21/68785 characterised by the mechanical construction of the susceptor, stage or support
• CPC Class Codes: H01L 21/68792 characterised by the construction of the shaft
• CPC Class Codes: Y10S 438/935 Gas flow control

Abstract

Vacuum CVD chambers are disclosed which provide a more uniformly deposited thin film on a substrate. The chamber susceptor mount for the substrate is heated resistively with a single coil firmly contacting the metal of the susceptor on all sides, providing uniform temperatures across the susceptor mount for a substrate. A purge gas line is connected to openings in the susceptor outside of the periphery of the substrate to prevent edge and backside contamination of the substrate. A vacuum feed line mounts the substrate to the susceptor plate during processing. A refractory purge guide, or a plurality of placement pins, maintain a fixed gap passage for the purge gases to pass alongside the edge of the wafer and into the processing area of the chamber. An exhaust pumping plate improves the uniformity of exhaustion of spent gases from the chamber.

Claims

1. A method of depositing a thin film onto a substrate with a precursor gas maintainable in a single substrate chemical vapor deposition chamber, comprising the steps of:

supporting the wafer on a susceptor heated to a temperature of from about 250°

to 650°

C. at a vacuum pressure; and

passing a purge gas from a plurality of openings in the susceptor located adjacent and outwardly of the edge of the substrate to prevent process gases from contacting the substrate edge.

2. The process of claim 1, wherein the precursor gas is WF6.

3. The process of claim 1, wherein the purge gas contains a reactive gas.

4. The process of claim 1, wherein the purge gas comprises a mixture of inert gas and hydrogen.

5. The process of claim 1, wherein the purge gas is directed against the underside of the edge of the substrate.

6. The process of claim 1, further including the step of

affixing the substrate to the susceptor by means of a vacuum.

7. A method of depositing a thin film onto a substrate in a single substrate chemical vapor deposition chamber, comprising the steps of:

supporting a substrate on a substrate support;

heating the substrate support by mounting a resistance heating coil within the substrate support;

passing a purge gas through a gap formed between the substrate and a purge gas source to prevent deposition on the outer edge of the substrate;

passing a deposition precursor gas into the chamber; and

uniformly exhausting gases from the periphery of the substrate and into an exhaust channel.

8. The method of claim 7, further comprising the steps of:

providing an ambient bore in the substrate support and terminating the bore immediately below the substrate receiving surface of the support member;

positioning a thermocouple within the bore and in contact with the mass of the support member; and

monitoring the temperature of the substrate support with the thermocouple.

9. A method of depositing a thin film onto a substrate in a single substrate chemical vapor deposition chamber comprising the steps of:

supporting a substrate on a substrate support;

preventing heat dissipation about the outer edge of the substrate;

passing a deposition precursor gas into the chamber; and

uniformly exhausting gases from the periphery of the substrate and into an exhaust channel.

10. The method of claim 9, further comprising the step of passing a purge gas through a gap formed between the substrate and a purge gas source to prevent deposition on the outer edge of the substrate.

11. The method of claim 10, further comprising the steps of:

providing an ambient bore in the substrate support and terminating the bore immediately below the substrate receiving surface of the support member;

positioning a thermocouple within the bore and in contact with the mass of the support member; and

monitoring the temperature of the substrate support with the thermocouple.

12. The method of claim 9 wherein the step of preventing heat dissipation comprises providing grooves in the substrate support under the outer edge of the substrate.

13. A method of depositing a thin film onto a substrate with a precursor gas maintainable in a single substrate chemical vapor deposition chamber, comprising the steps of:

supporting the wafer on a heated susceptor in the chamber;

passing a purge gas from a plurality of openings in the susceptor located outwardly of the edge of the substrate to prevent process gases from contacting the substrate edge; and

uniformly exhausting gases from the periphery of the substrate and into an exhaust channel.

14. The process of claim 13, wherein the precursor gas is WF₆.

15. The process of claim 13, wherein the purge gas contains a reactive gas.

16. The process of claim 13, wherein the purge gas comprises a mixture of inert gas and hydrogen.

17. The process of claim 13, wherein the purge gas is directed against the underside of the edge of the substrate.

18. The process of claim 13, further including the step of affixing the substrate to the susceptor by means of a vacuum.