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Contact Stud Fabrication Process Using Dual Ion-Beam Deposition and Etch

IP.com Disclosure Number: IPCOM000038381D
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Lee, P: AUTHOR [+2]

Abstract

A technique is described whereby a contact stud is formed using a dual ion-beam deposition and etch tool. As VLSI (very large-scale integration) scaling brings wiring dimensions down to the micron and sub-micron range, contact and via hole dimensions likewise shrink. This creates more problems in filling and planarizing contact holes. Fig. 1 shows a schematic of alternate deposition and etch steps utilizing a dual ion-beam deposition and etch tool to fabricate contact studs. The dual beam tool deposits material with one beam in a conventional sputter mode, and the other beam etches material using reactive ion beam etch techniques, i.e., a typical gas combination of chemical (CF4) and chemical ion assist (Ar) whose ratios are independently adjusted to gain the desired etch pattern.

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Contact Stud Fabrication Process Using Dual Ion-Beam Deposition and Etch

A technique is described whereby a contact stud is formed using a dual ion- beam deposition and etch tool. As VLSI (very large-scale integration) scaling brings wiring dimensions down to the micron and sub-micron range, contact and via hole dimensions likewise shrink. This creates more problems in filling and planarizing contact holes. Fig. 1 shows a schematic of alternate deposition and etch steps utilizing a dual ion-beam deposition and etch tool to fabricate contact studs. The dual beam tool deposits material with one beam in a conventional sputter mode, and the other beam etches material using reactive ion beam etch techniques, i.e., a typical gas combination of chemical (CF4) and chemical ion assist (Ar) whose ratios are independently adjusted to gain the desired etch pattern. Ion-beam deposition alone will not fill contact holes, but when deposition is alternated with in situ etch, then hole fill is possible. By adjusting the etch angle relative to the wafer, the top surface of the wafer is etched without etching in the contact hole. This technique allows material to accumulate in the contact holes without voids or pinching off at the top of the contact hole. Fig. 2 shows the extent of the hole fill capability which is limited by the dimensions of the contact hole and the minimum attainable angle between the wafer and etch beam. As the diameter of the contact hole increases, using a co...