US 2007/0177120 A1Published application

Photolithography equipment having wafer pre-alignment unit and wafer pre-alignment method using the same

AssigneeSamsung Electronics Co., Ltd.

InventorHee-Hwan Kim

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Abstract

Exposure equipment having a wafer pre-alignment apparatus and a wafer pre-alignment method using the same reduce wafer pre-alignment errors. The exposure equipment comprises a plurality of exposure units in which lots of wafers are loaded, respectively, and a central control unit. The exposure units are constituted by an alignment apparatus that can detect the relative angular orientation of each wafer transferred to the apparatus and thus, sense any misalignment of the wafers. The central control unit calculates inherent error values for the exposure units based on data transmitted to the central control unit from the alignment apparatus. The central control unit also controls the equipment based on the inherent error values of the exposure units to compensate for the misalignment of the wafers in the exposure units.

Claims17

Dependent claims

Photolithographic exposure equipment comprising:

a plurality of exposure units each constituted by an alignment apparatus having a sensor operative to detect the relative angular position of a wafer loaded into the exposure unit, and a rotary chuck, and an exposure apparatus including a wafer stage, a light source, and a reticle stage dedicated to support a reticle and optically interposed between the light source and the wafer stage;
and
a central control unit operatively connected to the sensor so as to receive data from the sensor representative of the relative angular position of each wafer transferred to the alignment apparatus, the central control unit including a processor configured to calculate an inherent error value for each of the exposure units from a sum of data received from the sensor after a number of wafers have been transferred in the exposure unit to the alignment apparatus, and a memory in which the respective inherent error values of the exposure units are correlated with the exposure units and stored, and the central control unit being operatively connected to the rotary chuck of the alignment apparatus so as to selectively rotate the chuck by an amount corresponding to the inherent error value of an exposure unit when a wafer is transferred in the exposure unit onto the rotary chuck.

A wafer pre-alignment method comprising:

transferring wafers from a standby location in an exposure unit to an alignment apparatus, detecting the relative angular positions of the wafers at the alignment apparatus, respectively, controlling the alignment apparatus to adjust the relative angular positions of each of the wafers by respective amounts necessary to set each of the wafers in the same relative angular position, whereby misalignment of the wafers with respect to a reference position is first compensated for, returning each of the wafers to the standby location, and calculating an inherent error value for the exposure unit based on the relative angular positions of the wafers detected when the wafers are at the alignment apparatus;
and
subsequently transferring the wafers in the exposure unit from the standby location back to the alignment apparatus, and controlling the alignment apparatus to adjust the orientation of the wafers each by an amount corresponding to the inherent error value calculated for the exposure unit, whereby misalignment of the wafers with respect to the reference position is secondly compensated for.

A wafer pre-alignment method comprising:

grouping wafers in lots and loading the lots of wafers into a plurality of exposure units, respectively, such that each of the lots is disposed at a respective standby location in each of the exposure units;
selecting one of the exposure units;
transferring wafers one-by-one from the respective standby location in the selected exposure unit to an alignment apparatus, detecting the relative angular position of the wafers at the alignment apparatus, and calculating an inherent error value for the selected exposure unit based on the detected relative angular positions of the wafers that were transferred to the alignment apparatus from the standby position in the selected exposure unit;
subsequently adjusting the respective orientations of the wafers in the selected exposure unit each by an amount corresponding to the inherent error value calculated for the exposure unit, whereby misalignment of the wafers in the selected exposure unit with respect to the reference position are compensated for;
and
repeating the above for each of the other exposure units such that respective inherent error values are calculated for each of the exposure units.

3 more elements

Dependencies are inferred from the claim text.