Photolithographic critical dimension control using reticle measurements

Abstract

A method of implementing a new reticle for manufacturing semiconductors on a wafer which involves performing measurements on the reticle and assigning an initial exposure dose by using a predetermined algorithm. The exposure control system utilizes reticle CD data for automatically calculating reticle exposure offset values, i.e. reticle factors. A correlation of reticle size deviations to calculated reticle factors is used to derive a reticle factor for the new reticle. The derived reticle factor is then used to predict an initial exposure condition for the new reticle which is applied to the lithography tool for achieving a wafer design dimension.

Description

technical field [0001] The present invention relates generally to the field of lithography; more particularly, to a method of achieving wafer design dimensions through a process control system using simple control algorithms and feedback. This feedback uses mask design data, mask dimension data, and historical wafer pattern measurements to center the critical dimension (CD) to the wafer pattern design dimensions. The present invention provides a way to control the feature size, ie critical dimension of lines or spaces, by ensuring that each wafer is processed using the correct exposure conditions, using different master measurements. Background technique [0002] In the field of integrated circuits (ICs), photolithography is used to transfer patterns, or images, from masks containing circuit design information to thin films on the surface of a substrate, such as a silicon wafer. Pattern transfer is accomplished with the aid of photoresists such as UV-sensitive organic polym...

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Problems solved by technology

Typically, this feedback arrangement does not account for the new mask bias, and the resulting production run does not meet the figure 1 The design size specification is 160

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