Alignment structure and alignment method of double-sided lithography machine

Abstract

Disclosed are a position matching structure and a position matching method for a two-sided stepper. The position matching structure comprises a primary "+" shaped position matching mark (10), and some secondary position matching marks (20) disposed above and under the primary position matching mark and in the left and right positions of the primary position matching mark. The "+" shaped primary position matching mark (10) is formed by a horizontal primary position matching mark (11) and a vertical primary position matching mark (12) vertically crossed. The secondary position matching mark (20) is stepped, and an each secondary position matching mark is formed by some rectangles with equal widths and some rectangles with lengths forming arithmetic progression. Position matching is performed by using a "+" shaped primary position matching mark and secondary position matching marks disposed above and under the primary position matching mark and in the left and right positions of the primary position matching mark, the present invention helps a naked eye distinguish matching positions and the positions matching precision is provided, thereby reducing an error due to the manual position matching and improving the production efficiency.

Description

technical field [0001] The invention relates to the technical field of semiconductor photolithography, in particular to an alignment mark structure and alignment method of a double-sided photolithography machine. Background technique [0002] There are many alignment methods that can be selected in double-sided lithography machines, such as infrared alignment, four-objective alignment, double-mask alignment, and grating phase alignment. However, there are certain defects in these alignment methods. Among them, the shortcomings of infrared alignment are: poor observation conditions of infrared microscope, low alignment accuracy, slow alignment speed, low productivity, when the wafer reaches a certain thickness, the infrared penetration ability is reduced, alignment is very difficult, and cannot It is used for wafer exposure that is not transparent to infrared light; the disadvantages of the four-objective lens alignment principle are: complex optical system, difficult design...

AI Technical Summary

Problems solved by technology

However, in these alignment methods, there are certain defects

Among them, the shortcomings of infrared alignment are: poor observation conditions of infrared microscope, low alignment accuracy, slow alignment speed, low productivity, when the wafer reaches a certain thickness, the infrared penetration ability is reduced, alignment is very difficult, and cannot It is used for wafer exposure that is not transparent to infrared light; the disadvantages of the four-objective lens alignment principle are: complex optical system, difficult design, assembly, and debugging, bulky and high equipment cost, inconvenient operation, and low productivity; double mask alignment The main disadvantages of the principle are: the equipment parts require high precision and complexity, and the exposure resolution is easily reduced due to mask deformation; the grating phase alignment is a very complicated system, which not only involves light, mechanics, electricity, materials, and processes and computer and other multidisciplinary theories, and the performance of any of the other subsystems of the lithography machine may affect the accuracy of the alignment system. In addition, since the grating alignment requires automatic scanning of precision workpiece tables, making This type of alignment has limited application in proximity contact optics

The MEMS double-sided lithography machine EVG620 completely manually places wafers and aligns them. The alignment accuracy of the machine is only 2 μm, which is relatively high; the machine error plus manual alignment (use the existing "+" word mark) , the alignment deviation of the manufactured product is relatively large, and the product cannot be satisfied in many cases, and rework is often required

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