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AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChia-Hui Lin, Chun Ming Wang
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A process to correct distortions due to optical proximity effects is described. A two reticle per pattern approach is used. The first, or primary, reticle contains the image that is to be transferred to the photoresist. It is used to expose the resist in the usual way to the correct dosage of light needed to optimally activate it. For a primary reticle bearing a line pattern, the second, or correction, reticle bears a pattern of rectangles which are located and dimensioned so that, when aligned relative to the primary reticle, they overlap all line ends in the pattern. The amount by which the rectangles overlap the lines is similar to the amount by which serifs (if they had been used) would overlap. The amount by which the rectangles extend outside the line ends is not critical (provided it is at least as large as the inside overlap amount). This property allows a single rectangle to be shared by many line ends. After the first exposure, the correction reticle is substituted for the primary reticle and, after alignment, a second, much shorter, exposure is given. The resist is then developed in the normal way, resulting in a patterned etch mask that is largely free of distortion. A similar approach applies to hole patterns except that a positive resist must be used.
A method for forming a photoresist mask, on a wafer, for generating, through etching, a line pattern having specific dimensions, including lines having ends, comprising:
A method for forming a photoresist mask, on a wafer, for generating, through etching, a hole pattern having specific dimensions, comprising:
A correction mask for overcoming distortion in an image formed in photoresist from a primary mask that includes a pattern of lines, some of which have ends, comprising:
A correction mask for overcoming distortion of an image of a hole having an edge, formed in positive photoresist from a primary mask, comprising:
Dependencies are inferred from the claim text.