fig4 shows a sectional view of a cell projection mask in accordance with an embodiment of the present invention . a cell projection mask 40 a includes a frame 31 a for supporting means , a membrane 32 a formed over the frame 31 a , for making a stress due to an electron beam to maintain balance and an absorber 33 a formed over the membrane 32 a , for absorbing or scattering the electron beam . the absorber 33 a is comprised of two or more layers 34 a , 34 b and 34 c which are selected from a silicon layer , polysilicon layer , sic layer , gaas layer , w layer , wsi x layer , al layer , ta layer , tin layer , pt layer , pb layer or si 3 n 4 layer . because the absorber 33 a has a stack structure , that is at least two or more different material layers 34 a , 34 b and 34 c , the thickness of the absorber 33 a is reduced compared to the silicon layer of the prior mask . distinctly speaking , the amount of the electrons reflected from a surface of the absorber to the electrons incident to the absorber is inversely proportional to the acceleration voltage of the electrons incident to the absorber and varied with the density and atomic weight of the material for the absorber . referring to fig5 suppose that the electrons 30 a incident to the absorber 33 a being comprised of multilayers made of materials different from each other , reflect in the interfaces between layers 34 a , 34 b and 34 c , respectively . accordingly , the amount of the electrons 30 b reflected from the absorber 33 a is increased . at this time , the more the incident electrons 30 a meet with the interface between the layers 34 a , 34 b and 34 c , the more the amount of the reflected electrons is largely increased . therefore , when the thickness of the silicon layer for the absorber is thinner than the penetration depth of the electrons , the amount of the electrons penetrating the silicon layer is increased . however , because most electrons incident to the absorber of a stack structure being comprised of different materials are reflected in the interface within the layers , it can reduce the thickness of the absorber . the electrons in the multi - layer absorber are scattered with a specific angle . in particular , of the scattered electrons , the electrons 30 d penetrating the side wall of the absorber has a critical scattering angle . at this time , the critical scattering angle is dependent on the acceleration of electrons , the thickness and the mean free path of the material for the absorber . in case where the silicon layer is used for the absorber , when the acceleration voltage of electrons is set at 50 kev and the silicon layer has a thickness of 1 μm , 10 μm and 20 μm , respectively , it is known that the critical scattering angle of the electrons scattering to the side wall of the silicon layer is 150 mrad , 750 mrad and 950 mrad , respectively , to the respective thickness of the silicon layer . however , when the silicon layer of 1 μm is stacked in ten layers , the critical scattering angle is not similar to 750 mrad which is the critical scattering angle in the silicon layer of 10 μm . actually , the electrons incident to the absorber where the silicon layer of 1 μm is stacked in ten layers or more , are scattering with the critical scattering angle of 150 mrad and they are continuously scattering with the critical scattering angle of 150 mrad while passing through the silicon layers of 1 μm . accordingly , the critical scattering angle penetrating the absorber of ten silicon layers becomes 1500 mrad which is ten times as large as the critical scattering angle in a single silicon layer of 1 μm . as a result , when the materials having the same critical scattering angle are stacked , the amount of the reflected electrons and the scattering angle are increased so that it can reduce the thickness of the silicon layer for the absorber and it can overcome difficulty in a process . fig6 shows a sectional view of a projection electron beam lithography mask in accordance with another embodiment of the present invention . a projection electron beam lithography mask 40 b includes a membrane 32 b being comprised of an oxide layer and a scatterer 33 b formed over the membrane 32 b , for making the electrons penetrating the membrane 32 b to be scattered at a selected angle . the scatterer 33 b is comprised of two or more layers 34 a , 34 b and 34 c like the absorber 32 a in fig4 . the layers 34 a , 34 b and 34 c of the scatterer 32 b are selected from a silicon layer , polysilicon layer , sic layer , gaas layer , w layer , wsi x layer , al layer , ta layer , tin layer , pt layer , pb layer or si 3 n 4 layer . if the electron beam is incident to the scatterer 33 b being comprised of different material layers 34 a , 34 b and 34 c , the electrons are scattered at a larger angle compared to a prior mask . accordingly , when an angular limiting aperture 15 including a transmitting portion 15 a and a shielding portion 15 b is disposed below the projection electron beam lithography mask 40 b , although the electrons penetrate the scatterer 33 b , they are scattered at the first critical scattering angle at the first interface between layers 34 a and 34 b and then are scattered at the second critical scattering angle at the second interface between the layers 34 b and 34 c again , when the electrons pass the scatterer 33 b being comprised of multi - layers 34 a , 34 b and 34 c having different materials , so that the electrons scattered to the side wall of the scatterer 33 b are shielded by the shielding portion 15 b of the angular limiting aperture 15 . as a result , the electrons scattered by the scatterer 33 b do not penetrate the angular limiting aperture 15 and the contrast and resolution can be improved . the angular limiting aperture 15 is applicable to the cell projection mask . according to the present invention , the absorber or the scatterer is formed by stacking two or more layers being comprised of different materials , so that it can reduce the thickness of the absorber or the scatterer and the processing time for etching the absorber or scatterer and it can obtain the desired patterns . furthermore , because the absorber or the scatterer has multi - layers , the scattering angle of the electrons is increased and the electrons penetrating the absorber or the scatterer have no effect on the electrons actually participating in patterning , thereby improving the resolution and the contrast . while the invention has been particularly shown and described with respect to preferred embodiment thereof , it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and the scope of the invention as defined by the following claims .