Mask loading technology

Abstract

The invention discloses a mask plate loading process, which belongs to the field of photolithography. During the operation of the existing reticle loading process, there are disadvantages such as large alignment errors, repeated calibration accuracy, and low loading efficiency. The reticle loading process of the present invention is used to accurately load the reticle onto the reticle carrier table of the lithography machine, the lithography machine has a mask transmission system and a mask table system, and the mask table system Including a reticle carrying table and a micro-movement table, the reticle loading process includes the following processes: (1) Retrieval of the reticle; (2) Rough pre-alignment; (3) Reticle transfer; (4) Fine pre-alignment. By adopting the invention, the precision of the whole mask plate loading process can reach: ±1 μm in x direction, ±1 μm in y direction, and ±0.05 mrad in rz direction. At the same time, the number of times of fine pre-alignment is reduced from the traditional 3-5 times to 1 time to achieve pre-alignment accuracy, which greatly improves the efficiency of pre-alignment and improves productivity.

Description

technical field [0001] The invention belongs to the field of photolithography, in particular to a mask plate loading process of a photolithography machine. Background technique [0002] In the lithography machine equipment, the alignment system has a limited capture range for the reticle mark, generally around 10 μm, and the maximum does not exceed 40 μm, which requires that the error of the reticle loaded to the carrier be controlled within a certain error range , otherwise the alignment system will fail because it cannot find the marker. [0003] Existing lithography machines have introduced a pre-alignment link in the mask plate loading process, such as the 6300 and 8000 lithography machines of GCA Corporation in the United States, which control errors through mechanical pre-alignment. Another example is the 2000 and 5000 lithography machines of ASML in the Netherlands, which control the loading error of the reticle through optical pre-alignment. In some lithography mac...

AI Technical Summary

Problems solved by technology

[0011] 1. The "fine pre-alignment" process cannot reduce the errors introduced by the "reticle handover" process

[0012] In the above-mentioned reticle loading process, the "reticle transfer" process is located after the "fine pre-alignment" process. In the "reticle transfer" process, due to factors such as assembly errors and vibrations between systems, new errors will be generated. And the process accuracy of "reticle handover" is often lower than that of "fine pre-alignment", which makes the error of loading process larger

[0013] 2. It is difficult to accurately calibrate the coordinate relationship between the mask plate transmission system and the mask table system

However, the mask transfer system and the mask stage system are independent of each other and exist in two coordinate worlds o 3 ’, o 1 ’, it is very difficult to accurately calibrate the coordinate relationship between the two systems, and there is a lack of effective measurement means and methods

If the coordinate relationship between the two systems is not calibrated accurately, the accuracy of the "fine pre-alignment" link will often fail to meet the requirements, or multiple pre-alignment actions will be required to meet the accuracy requirements, greatly reducing the loading efficiency

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