Browse Prior Art Database

Method for Producing Planarized Polysilicon Filled Trenches

IP.com Disclosure Number: IPCOM000038054D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Machesney, BJ: AUTHOR [+2]

Abstract

By using a recently developed high selectivity polysilicon to silicon dioxide (SiO2) or silicon nitride (Si3N4) chemical- mechanical polishing method, a single layer trench dielectric acts as an effective etch stop. Thus, a simplified process for filling trenches with polysilicon and planarizing is achieved. Stress induced crystal dislocations in substrate silicon near trench edges following isolation oxidation are reduced by the use of this process.

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Method for Producing Planarized Polysilicon Filled Trenches

By using a recently developed high selectivity polysilicon to silicon dioxide (SiO2) or silicon nitride (Si3N4) chemical- mechanical polishing method, a single layer trench dielectric acts as an effective etch stop. Thus, a simplified process for filling trenches with polysilicon and planarizing is achieved. Stress induced crystal dislocations in substrate silicon near trench edges following isolation oxidation are reduced by the use of this process.

Referring to Fig. 1, trench T is etched through SiO2 (oxide) layer 10 and into silicon (Si) substrate 12 leaving sidewall debris 14, which is also SiO2 . Sidewall debris 14 and oxide 10 are next removed by a wet etch.

As shown in Fig. 2, trench dielectric 16 (SiO2 and/or Si3N4) is conformally deposited. Next, polysilicon 18 is conformally deposited, and the high selectivity chemical-mechanical polishing process is used to planarize as shown.

Exposed trench insulation 18 is removed and normal isolation oxidation 20 is formed as shown in Fig. 3. The topology thus formed at the interface of oxide 20 and silicon substrate 12 is conducive to relatively low stress in the surface of silicon 12 with a result that there are fewer crystal dislocations to cause device leakage failures.

Disclosed anonymously.

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