Objective
UV2Litho aims to develop the necessary processes, which must enable the introduction of 157nm (or Vacuum-Ultra-Violet) lithography in pilot production lines as of 2004 when full field production 157nm step-and-scan systems will be introduced.
Amongst others, this project will have as major tasks to
(i) screen various possible resist options for 157nm and select, optimize and demonstrate the most manufacturable ones on critical layers of the 70nm technology node;
(ii) evaluate the printability of 157nm reticles for this same node; and finally
(iii) study metrology issues and propose solutions for practical 157nm lithography.
This project belongs to the MEDEA+ project FLUOR (SP4 and IMEC participation in SP3), but has been submitted to IST to fund the activities of a number of partners (IMEC, ST Agrate, ST Crolles, Philips, CNRS) in FLUOR which could not get funding through the regular channels.
Objectives:
157nm has only been seriously considered as the next optical lithography wavelength since about 18 months. Although a lot of potential showstoppers have been eliminated since than, risks remain and the biggest issue is the limited time to develop this new technology. As of 2005, some advanced IC manufacturers want to start integrating 157nm in their pilot lines. All major exposure tool vendors have started extensive development to come up with the first full-field exposure tools as of 2003-2004. One of the biggest challenges is to make sure that a pilot line resist process can be integrated when the first exposure tools come out.
The UV2Litho project has the following objectives:
(i) to accelerate the development of manufacturable resist processes;
(ii) to demonstrate 157nm resist solutions for the 70nm node;
(iii) to provide feedback to the mask making industry on the printing performance or early 157nm reticles and
(iv) to provide feedback to the resist suppliers to guide their development.
Work description:
In order to accelerate the progress on 157nm process development, IMEC is currently building up a 157nm lithography infrastructure, that must be operational in the first quarter of 2002. A lot of groundbreaking work on 157nm resists is currently being carried out at Int.'l Sematech or Selete, where small field steppers have become operational in 2000. These tools are however limited in the sense that, although available today, their imaging properties are quite far away from the properties of the full field step and scan tools that will be introduced for manufacturing: the NA is limited to 0.6 (versus 0.8 targeted on manufacturing), the field size is only 1.5mm which makes it difficult to cover a full wafer in a representative way with patterns for dry etch development, and the mask reduction is 10x (versus 4x or 5x for manufacturing). The infrastructure at IMEC will consist of a mid-field exposure tool, equipped with a 0.75 NA lens, a 4mm field, and a reticle magnification of 6x.
These properties are already very close to the properties of a full field exposure tool and therefore the process development program carried out under the IMEC infrastructure can be regarded as a follow-up phase of the programs currently running in the US and Japan. Resists from various vendors will be screened continuously on the mid-field stepper. The most promising resists will be optimised for integration in 70nm critical layers (gate, contact). The capability of 157nm lithography will be demonstrated on the mid-field exposure tool first and towards the end of the project on a full field scanner. Also metrology issues for 157nm lithography will be investigated and solutions proposed where necessary.
Moreover, the development will be supported by simulations. Finally, the printability of early 157nm reticles, provided by commercial mask shops will be evaluated on the mid-field exposure tool, and feedback will be given to the mask.
Milestones:
The required specifications and acceptance tests for the full-field exposure systems will be derived. The capability of the most promising 157nm resist processes, integrated in critical layers on the 70nm node, will be demonstrated. Metrology issues for 157nm line width will be identified and solutions proposed. A set of mask specifications for 157nm full field step and scan tools will result out of this work.
Call for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
3001 LEUVEN
Belgium