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0.5 Micron X-Ray Lithography: Sources, Masks, Resist and Transferred Image

Objective

The project aimed to develop a technology compatible with X-rays from 7 to 13 , so that resolution down to 0.25 micron may be eventually achieved.
The main tasks of this project were: Masks, Resist and XRay Lithography Process.
Masks
-Non-hydrogenated SiC membranes are fully operational on 2" wafers. Transfer of the process to 4" wafers was shown to be feasible.
-In pattern transfer, <0.5 micron resolution was achieved by two techniques:
.A subtractive technique, consisting of tungsten R.I.E. involving a trilevel resist process. It was shown to be fully compatible with <0.5 micron dimensions. The technique was analysed in relation to stress, ebeam patterning and quality of image transfer.
.Electroplating of Au by a single-layer resist process was achieved. The process was fully consolidated and characterised. Furthermore, a new process was presented allowing the use of thinner absorber structures (34000). Finally, experiments of mask copying by Xray lithography were carried out.
Resists
-The development of an original positive fluorinated resist was optimised. An original negative resist (PVS) was tested and compared with the silicon negative resist from TOYO SODA and negative MESE resist from Japan synthetic rubber.
XRay Lithography Process
-The MX 1600 XRay stepper from Micronix was operational within the project. Furthermore, the development work of the laser plasma source provided the project with the most promising alternative source to compact synchrotrons.
The project aimed to develop a technology compatible with X-rays from 7 angstroms to 13 angstroms, so that resolution down to 0.25 micron may be eventually achieved. The main tasks of this project were:
masks;
resist;
X-ray;
lithography process.

Nonhydrogenated silicon carbide membranes are fully operational on 2 inch wafers. Transfer of the process to 4 inch wafers was shown to be feasible. In pattern transfer, less than 0.5 micron resolution was achieved by 2 techniques:
a subtractive technique, consisting of tungsten reactive ion etching involving a trilevel resist process;
electroplating of gold by a single-layer resist process.

The development of an original positive fluorinated resist was optimised.

The MX 1600 X-ray stepper from Micronix was operational within the project. The development work of the laser plasma source provided the project with the most promising alternative source to compact synchrotrons.

Coordinator

Consiglio Nazionale delle Ricerche (CNR)
Address
Via Cineto Romano 42
00156 Roma
Italy

Participants (4)

Centre National de la Recherche Scientifique (CNRS)
France
Address
15 Quai Anatole France
75700 Paris
KING'S COLLEGE LONDON
United Kingdom
Address
Strand
London
Thomson CSF
France
Address
Domaine De Corbeville
91404 Orsay
Thomson Microelectronics Srl (SGS)
Italy
Address
Via Carlo Olivetti
20041 Agrate Brianza Milano