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由掩模、步进机、光刻工艺和计量仪器产生的误差影响着光刻套准。为此,推出一种检查掩模自身精度的新方法,它能为圆片加工提供更实用的基准,并可反映出其它误差量。研究表明,掩模厚度是决定掩模上图形位置精度的一个关键因素。衬底越厚,自身的畸变越小,掩模制作中连续加工引起的变形越小。尽管厚衬底掩模的像场几乎比薄衬底大1 倍,但6-35 m m 厚度石英衬底掩模的置位图形比2-29 m m 厚度的更准确。离轴照明(OAI) 是影响套准的另一原因,它可引发镜头像差,通过芯片倍率和旋转控制可以补偿这种误差。接触孔制作的套准控制非常重要,但相当困难,多层构造的接触孔套准控制更难。目前试制了一种分别控制x、y 向套准的方法,其是解决多层构造接触孔套准控制的一种很有潜力的方法
The errors produced by masks, steppers, lithography, and metrology tools affect lithography registration. To this end, a new method of inspecting the mask’s own accuracy is introduced, which provides a more practical basis for wafer processing and reflects other error quantities. Research shows that the mask thickness is a key factor in determining the position accuracy of the pattern on the mask. The thicker the substrate, the smaller its own distortion, and the less distortion that can be caused by the continuous processing of the mask. Although the thick substrate mask has an image field almost one time larger than the thin substrate, the 6-35 m thick quartz substrate mask has a more accurate setting pattern than the 2-29 μm thickness. Off-axis illumination (OAI) is another factor that affects registration because it can induce lens aberrations that can be compensated for by chip override and rotation control. Registration control of contact holes is very important, but rather difficult, contact hole registration control of multi-layer structures is more difficult. At present, a method of separately controlling the registration of x and y is developed, which is a promising method for solving the problem of register control of contact holes in a multi-layer structure