Double-sided lithographic method

Abstract

The invention discloses a double-sided lithographic method. The method comprises the steps of: making first alignment marks (101) on one or both sides of a substrate requiring photolithography (100); aligning the photomask and the substrate (100) for the first photolithography by using the first alignment marks (101), and making second alignment marks (103) on the substrate (100); and aligning the photomask with the substrate (100) for subsequent photolithography by using the second alignment marks (103) and making subsequent patterns on the substrate (100), wherein the accuracy of the first alignment marks (101) is higher than that of the second alignment marks (103). The above method can prevent offset of the patterns on the substrate.

Description

technical field [0001] The invention relates to semiconductor manufacturing, in particular to a zero exposure method for a double-sided photolithography machine. Background technique [0002] In the semiconductor process, double-sided processing technology is required in some cases, for example, graphics need to be made on both the front and back sides of the silicon wafer, or when the size of the chip is greater than 2mm. Double-sided processing technology requires the use of special equipment double-sided lithography machine. [0003] The double-sided lithography machine adopts proximity or contact exposure, that is, the optical system projects the pattern on the silicon wafer at a ratio of 1:1. Therefore, the size of the mask used is the same as that of the silicon wafer, and the size and position of the pattern on the mask must also be consistent with the actual situation. In this way, the traditional double-sided photolithography process basically uses manual methods ...

AI Technical Summary

Problems solved by technology

However, inaccurate alignment is common in manual placement of masks, including center deviation, that is, the center of the exposure pattern will deviate from the center of the wafer, and the maximum deviation will reach more than ten millimeters; it also includes rotation deviation, that is, the exposure pattern is relative to the wafer. The flat side of the circle will rotate, up to tens of degrees

Although skilled workers can overcome this problem to a large extent, alignment accuracy is still affected by operating proficiency

Images