Browse Prior Art Database

Process for Borderless Contacts to Silicon

IP.com Disclosure Number: IPCOM000037949D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Kaanta, CW: AUTHOR [+2]

Abstract

By adding an etch stop layer and using selectively deposited tungsten as an etch stop in exposed silicon contact regions, borderless contacts are made to silicon at varying depths under an insulator. Contacts made by this technique use minimum area without adding photo-masking steps.

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Process for Borderless Contacts to Silicon

By adding an etch stop layer and using selectively deposited tungsten as an etch stop in exposed silicon contact regions, borderless contacts are made to silicon at varying depths under an insulator. Contacts made by this technique use minimum area without adding photo-masking steps.

Referring to Fig. 1, standard processing is used to form polysilicon line 2 over insulator 4 on silicon substrate 6 having a diffusion region 8. Next, thick insulator 10 and etch stop layer 12 is deposited over the entire surface. A contact hole pattern is next defined by normal photo processing. Then etch stop layer 12 is removed from contact hole regions A and B. Next insulator 10 is anisotropically etched until polysilicon 2 is exposed. Photo resist (not shown) may then be removed and tungsten (W) 14 is selectively deposited on exposed silicon.

Referring to Fig. 2, anisotropic contact hole etching through remaining insulator 10 in contact region A is completed to expose the surface of diffusion 8 in substrate 6, thus completing the cross section shown in Fig. 2. Note that W 14 prevented etching in contact hole B. Contact holes in regions A and B are then filled with a conductor and integrated circuit wiring is completed by standard processing methods.

Disclosed anonymously.

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