Testing method of porosity of porous low k material

Abstract

The invention discloses a testing method of the porosity of a porous low k material. The method comprises the steps that an imporous low k dielectric layer and a porous low k dielectric layer are deposited on two wafers respectively, wherein whether a pore-foaming agent is led or not is used as the distinguishing condition; the density, obtained through calculation, of the imporous low k dielectric layer is used as the true density of the compact imporous low k dielectric layer in the ideal state when the mass and volume method is used for measuring the porosity; the porosity of the porous low k dielectric layer is obtained through the relative method. Thus, non-destructive testing of the porosity of the porous low k dielectric layer is realized, and the defects that when the mass and volume method is used for testing the porosity in the prior art, samples need to be damaged, steps are complex and inaccuracy is prone to being generated are overcome. Thus, the testing method has the advantages of being simple and easy to operate and low in cost, and meanwhile guarantees the testing accuracy.

Description

technical field [0001] The invention relates to the technical field of measurement of semiconductor integrated circuits, in particular to a method for testing the porosity of porous low k materials. Background technique [0002] With the development of CMOS integrated circuit manufacturing process and the reduction of critical dimensions, many new materials and processes are applied to the device manufacturing process to improve device performance. Among them, porous low k (low dielectric constant) materials are widely used because they can achieve a dielectric constant below 2.7 and can effectively reduce the RC delay of integrated circuits. [0003] Currently, the formation of porous low k materials (mainly BD2: Black Diamond 2) can be divided into two steps: thin film deposition and UV irradiation. Thin film deposition is done in a PECVD reaction chamber, and an organic porogen (ATRP) is introduced during the process. The initial film deposited was not porous and contai...

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Problems solved by technology

[0010] The purpose of the present invention is to overcome the above-mentioned defects existing in the prior art, and to provide a method for testing the porosity of porous low k materials, by adopting the same deposition conditions on two wafers to deposit a non-porous low k dielectric layer and a porous low k dielectric layer respectively. k medium layer, and the calculated density of the non-porous low k medium layer is used as the true density of the material when the porosity is measured by the mass volume method, and the porosity of the porous low k medium layer is obtained, so as to realize the porosity analysis of the porous low k medium layer Therefore, it eliminates the defects that the existing mass-volume method needs to destroy the sample, the steps are complicated and the defects are easy to be misaligned when measuring the porosity. This test method is simple and easy, and the accuracy of the test is guaranteed.

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