Anisotropic deposition of silicon dioxide

• US 5,013,691 A
• Filed: 07/31/1989
• Issued: 05/07/1991
• Est. Priority Date: 07/31/1989
• Status: Expired due to Term

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.), Agere Systems Guardian Corp. (Broadcom, Inc.)
• Original Assignee: AT&T, Inc.
• Inventors: Olmer, Leonard J., Lory, Earl R.
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): Guffin, Andrew
• Application Number:
  US07/386,650
• Time in Patent Office: 645 Days
• Field of Search: 437/238, 437/240, 437/243, 148/DIG. 118
• US Class Current: 438/789
• CPC Class Codes: C23C 16/402 Silicon dioxide
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/76837 Filling up the space between adjacent conductive structures; Gap-filling properties of dielectrics
• CPC Class Codes: Y10S 148/118 Oxide films

Abstract

In a radio-frequency plasma deposition reactor (10), SiO₂ is deposited from a source (16) of tetraethoxysilane (TEOS). The deposition is made to be anisotropic, that is, to be deposited preferentially on horizontal surfaces, by use in the deposition atmosphere of a constituency such as NH₃ or NF₃ which inhibits SiO₂ deposition, along with a radio-frequency power in excess of 100 watts, which preferentially removes the inhibiting gas from horizontal surfaces through ion impact.

Claims

1. A method for making an integrated circuit device comprising the steps of depositing silicon dioxide on a substrate by subjecting the substrate to a radio-frequency plasma in an atmosphere including a source of silicon and a source of oxygen, characterized in that:

there is introduced into the atmosphere an inhibiting gas that inhibits the deposition of silicon dioxide on the substrate surface;

and the radio-frequency plasma is formed by subjecting the atmosphere to radio-frequency power in excess of 100 watts, whereby the density of said inhibiting gas is reduced on horizontal surfaces of the substrate with respect to vertical surfaces of the substrate, thereby promoting preferential silicon dioxide deposition on the horizontal surfaces.

2. The method of claim 1 further characterized in that:

the source of silicon comprises tetraethoxysilane.

3. The method of claim 1 further characterized in that:

the inhibiting gas comprises NH₃.

4. The method of claim 1 further characterized in that:

the inhibiting gas comprises NF₃.

5. The method of claim 2 further characterized in that:

the atmosphere includes oxygen and an inert gas.

6. The method of claim 2 further characterized in that:

the radio-frequency plasma is produced by parallel first and second electrodes, the first electrode being connected to a radio-frequency power source, the second electrode being grounded, and the substrate is supported on one of the electrodes,

and the inhibiting gas is a gas that strongly adsorbs to the substrate.

7. The method of claim 6 further characterized in that the inhibiting gas comprises NH₃.

8. The method of claim 6 further characterized in that the inhibiting gas comprises NF₃.

9. A method for making integrated circuits comprising the steps of:

forming a first metal conductor pattern over a semiconductor substrate, placing the substrate on one electrode of a radio-frequency reactor having two electrodes, introducing into the reactor an atmosphere including tetraethoxysilane, exciting with radio-frequency power one electrode of the reactor so as to cause silicon dioxide to be deposited on the substrate, characterized in that;

the excited electrode is excited with radio-frequency power in excess of 100 watts;

and the atmosphere includes a gas that inhibits deposition of silicon dioxide on the substrate.

10. The method of claim 9 further characterized

the inhibiting gas is selected from the group consisting of NH₃ and NF₃.

11. The method of claim 10 further characterized in that:

the atmosphere further includes oxygen.

12. The method of claim 11 further characterized in that:

one of the two radio-frequency electrodes is excited by radio-frequency energy, a second one of the two electrodes is grounded, and the substrate is contained on the second electrode.

13. The method of claim 9 further characterized in that:

the silicon dioxide is deposited to a thickness that exceeds half the separation distance of two adjacent conductors of the first metal conductor pattern.

14. The method of claim 12 further characterized in that:

a second metal conductor pattern is formed over the deposited silicon dioxide.

15. The method of claim 13 further characterized in that:

the upper surface of the silicon dioxide is planarized and thereafter a second metal conductor pattern is formed over the planarized silicon dioxide surface.

16. The method of claim 15 is further characterized in that:

after planarization a second coating of silicon dioxide is deposited on the planarized silicon dioxide and thereafter the second metal conductor pattern is formed on the second coating of silicon dioxide.