Shadow projection mask for ion implantation and ion beam lithography
First Claim
1. A projection mask comprising;
- a thin P+ -doped silicon layer having through holes adapted to the mask pattern, a grid supporting said silicon layer in areas where holes are not present, said grid comprising silicon ribs doped differently from the silicon layer and having on at least an upper side facing away from the grid an ion-absorbing layer, said grid on at least the surface exposed to ion radiation being electrically and thermally conductive, said silicon layer and said grid defining a silicon frame, a coating disposed on said frame where it is to be exposed to the ion beams having at least such a thickness, taking into consideration the ion energy and the characteristics of the covering material, preventing ion penetration into the silicon, said mask surface exposed to the ion radiation comprising a material resistant to the ion attack, and said silicon frame coating not causing mask deformation due to temperature and/or inherent tensions of the coating.
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Accused Products
Abstract
A projection mask comprises a thin P+ -doped silicon layer with through holes adapted to the mask pattern, a grid supporting this layer having silicon ribs. On at least on its side facing away from the grid, the layer has a layer, which is at least as thick as to prevent the implanting of ions in the silicon layer. At least the mask surface exposed to ion irradiation is electrically and thermally conductive, and mechanically resistant. The coating of the silicon frame of the mask is such that it does not cause any mask deformation caused by temperature and/or through inherent tensions of the coating. Preferred absorbing materials are gold, silver, platinum, tungsten, and tantalum, and mechanically resistant materials are preferably carbon, molybdenum, titanium, tungsten, and tantalum. In operation, the mask with grid is placed onto the substrate to be irradiated, and subsequently blanket-illuminated with an ion beam, or scanned line-by-line until each point on the mask has been covered by the beam path.
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Citations
13 Claims
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1. A projection mask comprising;
- a thin P+ -doped silicon layer having through holes adapted to the mask pattern, a grid supporting said silicon layer in areas where holes are not present, said grid comprising silicon ribs doped differently from the silicon layer and having on at least an upper side facing away from the grid an ion-absorbing layer, said grid on at least the surface exposed to ion radiation being electrically and thermally conductive, said silicon layer and said grid defining a silicon frame, a coating disposed on said frame where it is to be exposed to the ion beams having at least such a thickness, taking into consideration the ion energy and the characteristics of the covering material, preventing ion penetration into the silicon, said mask surface exposed to the ion radiation comprising a material resistant to the ion attack, and said silicon frame coating not causing mask deformation due to temperature and/or inherent tensions of the coating.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
Specification