公开(公告)号：US5458999A

公开(公告)日：1995-10-17

申请号：US82243

申请日：1993-06-24

申请人： Gabor Szabo ,  Frank K. Tittel ,  Joseph R. Cavallaro ,  Motoi Kido

发明人： Gabor Szabo ,  Frank K. Tittel ,  Joseph R. Cavallaro ,  Motoi Kido

IPC分类号： G03F1/26 ,  G03F1/29 ,  G03F7/20 ,  G03F9/00

CPC分类号： G03F1/26 ,  G03F1/29 ,  G03F7/70283 ,  G03F7/70408

摘要： A phase shifting method uses a special interferometer in which the illuminating beam is divided into two or more components and the mask is irradiated from both sides. The pattern to be transferred onto the wafer (the mask) is generated on an optically transmissive substrate by appropriately combining reflective, transparent and absorptive areas. The optical paths of the beams illuminating the back side and the front side of the mask (that will be called transmitted and reflected beams respectively) are chosen so that the phase of the two beams is different by approximately an odd multiple of .pi. radians at the surface of the mask. The combined beams are projected onto the target wafer by suitable optics. The phase difference between the illuminating beams reduces the edge blurring that results from diffraction effects. This steepens the slope of the intensity profile at the edge of the features making it possible to achieve smaller feature sizes in the microlithographic replication without using those phase shifting elements of the conventional phase shifting method which made mask fabrication difficult. As a consequence of the lack of the phase shifting layers, the wavelength range of the method of this invention can easily be extended towards shorter wavelengths, and, further, the new mask is less vulnerable to optical damage. The additional freedom that the phase relation and intensity of the beams can be varied continuously allows for optimization that can lead to improved resolution, compared to conventional phase shifting techniques.

摘要翻译： 相移方法使用特殊的干涉仪，其中将照明光束分成两个或更多个部件，并且从两侧照射该掩模。 通过适当地组合反射，透明和吸收区域，在透光性基板上产生要转印到晶片上的图案（掩模）。 选择照射掩模的背侧和前侧（分别被称为透射和反射光束）的光束的光路，使得两个光束的相位在 表面的面具。 组合的光束通过合适的光学器件投射到目标晶片上。 照明光束之间的相位差减少了由衍射效应引起的边缘模糊。 这使得特征边缘处的强度分布的斜率变浅，使得可以在微光刻复制中实现更小的特征尺寸，而不需要使得难以进行掩模制造的常规相移方法的那些相移元件。 由于缺少相移层，本发明方法的波长范围可以容易地扩展到更短的波长，而且新的掩模不太容易受到光学损伤。 与传统的相移技术相比，光束的相位关系和强度可以连续变化的附加自由度允许优化，这可以导致改进的分辨率。