Patent Number: 
Section: claims

1. A multilayer film reflective mirror comprising a first multilayer film which is formed by alternately laminating layers comprising a first substance having a thickness and layers comprising a second substance, having a thickness, on a substrate, and a second multilayer film which is formed on the first multilayer film, and which is formed by alternately laminating layers comprising the first substance having a thickness and layers comprising the second substance having a thickness,wherein a difference between the refractive index of the first substance in the soft X-ray region and the refractive index first multilayer film is 50% to 120% of the thickness of the layer comprising the first substance in the second multilayer film. 2. The multilayer film reflective mirror according to claim 1, wherein the thickness of the layer comprising the first substance in the. 3. An X-ray exposure apparatus comprising an X-ray light source that generates X-rays, an illumination optical system that conducts X-rays from this X-ray light source to a mask, and a projection optical system that conducts the X-rays from the mask to a photosensitive substrate, and which transfers the pattern of the mask to the photosensitive substrate, wherein at least one part selected from the group consisting of the illumination optical system, the mask and the projection optical system comprises the multilayer film reflective mirror according to claim 2. 4. The multilayer film reflective mirror according to claim 1, wherein the first multilayer film has an internal stress that counteracts the internal stress of the second multilayer film. 5. An X-ray exposure apparatus comprising an X-ray light source that generates X-rays, an illumination optical system that conducts X-rays from this X-ray light source to a mask, and a projection optical system that conducts the X-rays from the mask to a photosensitive substrate, and which transfers the pattern of the mask to the photosensitive substrate, wherein at least one part selected from the group consisting of the illumination optical system, the mask and the projection optical system comprises the multilayer film reflective mirror according to claim 3. 6. The multilayer film reflective mirror according to claim 1, wherein the Γ value of the first multilayer film is greater than the Γ value of the second multilayer film. 7. An X-ray exposure apparatus comprising an X-ray light source that generates X-rays, an illumination optical system that conducts X-rays from this X-ray light source to a mask, and a projection optical system that conducts the X-rays from the mask to a photosensitive substrate, and which transfers the pattern of the mask to the photosensitive substrate, wherein at least one part selected from the group consisting of the illumination optical system, the mask and the projection optical system comprises the multilayer film reflective mirror according to claim 6. 8. The multilayer film reflective mirror according to claim 1, wherein the first substance is molybdenum of a vacuum is larger than a difference between the refractive index of the second substance in the soft X-ray region and the refractive index of a vacuum,the thickness of the layer comprising the first substance in the first multilayer film is substantially equal to or smaller than the thickness of the layer comprising the first substance in the second multilayer film, and a Γ value of the first multilayer film differs from a Γ value of the second multilayer film, and is larger than 0.5,wherein the Γ value is a ratio of the thickness of the layer of the first substance to a periodic length, and the periodic length is the sum of the thickness of the layer of the first substance and the thickness of the layer of the second substance. 9. An X-ray exposure apparatus comprising an X-ray light source that generates X-rays, an illumination optical system that conducts X-rays from this X-ray light source to a mask, and a projection optical system that conducts the X-rays from the mask to a photosensitive substrate, and which transfers the pattern of the mask to the photosensitive substrate, wherein at least one part selected from the group consisting of the illumination optical system, the mask and the projection optical system comprises the multilayer film reflective mirror according to claim 8. 10. The multilayer film reflective mirror according to claim 1, wherein the second substance is silicon. 11. An X-ray exposure apparatus comprising an X-ray light source that generates X-rays, an illumination optical system that conducts X-rays from this X-ray light source to a mask, and a projection optical system that conducts the X-rays from the mask to a photosensitive substrate, and which transfers the pattern of the mask to the photosensitive substrate, wherein at least one part selected from the group consisting of the illumination optical system, the mask and the projection optical system comprises the multilayer film reflective mirror according to claim 10. 12. A multilayer film reflective mirror comprising a first multilayer film which is formed by alternately laminating molybdenum layers having a thickness and silicon layers having a thickness, on a substrate, and a second multilayer film which is formed on the first multilayer film, and which is formed by alternately laminating molybdenum layers having a thickness and silicon layers having a thickness, wherein the thickness of the molybdenum layer in the first multilayer film is 1.2 nm to 3 nm, and a Γ value of the first multilayer film differs from a Γ value of the second multilayer film, and is larger than 0.5,wherein the Γ value is a ratio of the thickness of the molybdenum layer to a periodic length, and the periodic length is the sum of the thickness of the molybdenum layer and the thickness of the silicon layer. 13. An X-ray exposure apparatus comprising an X-ray light source that generates X-rays, an illumination optical system that conducts X-rays from this X-ray light source to a mask, and a projection optical system that conducts the X-rays from the mask to a photosensitive substrate, and which transfers the pattern of the mask to the photosensitive substrate, wherein at least one part selected from the group consisting of the illumination optical system, the mask and the projection optical system comprises the multilayer film reflective mirror according to claim 1. 14. An X-ray exposure apparatus comprising an X-ray light source that generates X-rays, an illumination optical system that conducts X-rays from this X-ray light source to a mask, and a projection optical system that conducts the X-rays from the mask to a photosensitive substrate, and which transfers the pattern of the mask to the photosensitive substrate, wherein at least one part selected from the group consisting of the illumination optical system, the mask and the projection optical system comprises the multilayer film reflective mirror according to claim 12. 15. A multilayer film reflective mirror comprising a first multilayer film which is formed by alternately laminating layers comprising a first substance having a thickness and layers comprising a second substance having a thickness, on a substrate, and a second multilayer film which is formed on the first multilayer film, and which is formed by alternately laminating layers comprising the first substance having a thickness and layers comprising the second substance having a thickness,wherein a difference between the refractive index of the first substance in the soft X-ray region and the refractive index of a vacuum is larger than a difference between the refractive index of the second substance in the soft X-ray region and the refractive index of a vacuum,the thickness of the layer comprising the first substance in the first multilayer film is substantially equal to or smaller than the thickness of the layer comprising the first substance in the second multilayer film, andthe first multilayer film has tensile stress and the second multilayer film has compressive stress. 16. An X-ray exposure apparatus comprising an X-ray light source that generates X-rays, an illumination optical system that conducts X-rays from this X-ray light source to a mask, and a projection optical system that conducts the X-rays from the mask to a photosensitive substrate, and which transfers the pattern of the mask to the photosensitive substrate, wherein at least one part selected from the group consisting of the illumination optical system, the mask and the projection optical system comprises the multilayer film reflective mirror according to claim 15.