Ammonia concentration detection method and photoetching process figure critical dimension (CD) control method

Abstract

The invention provides an ammonia concentration detection method. The ammonia concentration detection method is used for detecting a concentration of ammonia in a photoetching machine. The method comprises S1, providing a wafer and forming light resistance on the wafer, S2, carrying out light resistance imaging to obtain a light resistance figure, wherein the light resistance figure comprises at least one first area influenced by ammonia in the photoetching machine and at least one second area uninfluenced by ammonia in the photoetching machine, wherein the first area and the second area are uniformly distributed on the wafer, S3, selecting the at least one first area and the at least one second area and carrying out critical dimension (CD) measurement to obtain at least one first CD and at least one second CD, and S4, according to the size difference of the first SD and the second CD, calculating an ammonia concentration in the photoetching machine. The method utilizes a CD measurement method to detect an ammonia concentration in the photoetching machine, produces minimum influence on photoetching machine production and realizes frequent detection.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for detecting ammonia gas concentration and a method for controlling pattern CD in a photolithography process. Background technique [0002] ASML (ASMLHoldingN.V.) is a semiconductor equipment manufacturer in the Netherlands. The main products of ASML are the stepper lithography machine (Stepper), which is the core equipment used to produce large-scale integrated circuits, and the scanning lithography machine (Scanner), which is used to manufacture integrated circuits with 37nm line width. For ASML's Scanner, in the lithography process (LithoProcess), it is necessary to strictly control the time of the wafer from the exposure unit to the hot plate (HotPlate) of the postexposure bake (PostExposureBake, PEB) unit after exposure, which is generally required. Controlled within 400 seconds, the interval between the exposure unit and the post-exposure bake unit is call...

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Problems solved by technology

[0008] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a method for detecting the concentration of ammonia gas and a method for controlling the pattern CD in the photolithography process, which is used to solve the problems caused by the internal problems of the photolithography machine in the prior art. The detection of the ammonia concentration in the lithography machine will affect the production operation of the lithography machine, so the problem that it cannot be detected frequently, and solve the problem that the detection method of the prior art is used due to the uneven distribution of the ammonia gas concentration inside the lithography machine. , the problem of low accuracy of the ammonia gas concentration inside the lithography machine is obtained. In addition, it also solves the problem that the existing technology cannot control the CD of the pattern in the lithography process according to the influence of the ammonia gas concentration on the CD, resulting in the lithography When the exposed photoresist in the process is delayed in baking after exposure, it is affected by the ammonia gas inside the lithography machine, which leads to CD changes and wafer defects.

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