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Browse Prior Art Database

Self Aligned Stud With Dual Insulator

IP.com Disclosure Number: IPCOM000049162D
Original Publication Date: 1982-May-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Bartush, TA: AUTHOR [+3]

Abstract

The process described here is directed to interconnecting studs between multilevel metallurgies, with reduced photolithographic steps and interlevel shorts.

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Self Aligned Stud With Dual Insulator

The process described here is directed to interconnecting studs between multilevel metallurgies, with reduced photolithographic steps and interlevel shorts.

Apply a modified photoresist lift-off structure to the planar structure shown in Fig. 1.

The preferred barrier layer in the lift-off structure is 4000 A SiO(x) which has a slower etch rate than nitride in CF(4). This will prevent the SiO(x) layer from being depleted in the final lift-off etch cycle.

The RIE (reactive ion etching) lift-off etch cycle is as follows:

Etch in CF to remove the SiO(x) barrier; switch to O(2) to remove the underlayer photoresist and then back to CF(4) to remove the lOOOA nitride from the contact areas. See Fig. 2.

Deposit the metal (and lift-off metal) over the structure. The studs thus formed will be deposited in the nitride openings, thereby self-aligned since the same lift-off structure was used to etch the nitride openings and also to deposit the stud. The second quartz is deposited and etched back to reveal the studs. See Fig. 3.

The final structure will then have self-aligned studs and a nitride layer sandwiched between first and second quartz.

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