Semiconductor interconnection structure and preparation method thereof

Abstract

The invention provides a semiconductor interconnection structure and a preparation method thereof, and the method comprises the following steps: 1), providing a substrate, forming a dielectric layer on the upper surface of the substrate, and forming a contact hole in the dielectric layer; 2) performing shape adjustment on the top opening of the contact hole to enable the side wall of the contact hole to comprise a vertical side wall and an inclined side wall; 3) forming a seed layer at the bottom of the contact hole, the vertical side wall, the inclined side wall and the upper surface of the dielectric layer; 4) forming a metal layer on the seed layer in the contact hole in an electroplating mode at least including multi-stage current density gradual increase; and 5) annealing the structure obtained in the step 4), so that the metal layer fills the contact hole in a hole-free filling manner. According to the invention, the top morphology of the contact hole is adjusted before the metallayer is filled, so that the generation of overhang can be effectively avoided; and annealing treatment is carried out, so that the metal layer can fill the contact hole in a hole-free manner, the resistance value of the filling metal layer is reduced, and the reliability of the device is improved.

Description

technical field [0001] The invention belongs to the technical field of integrated circuit manufacturing, and in particular relates to a semiconductor interconnection structure and a preparation method thereof. Background technique [0002] Among existing semiconductor processes, tungsten film deposition using chemical vapor deposition (CVD) is a common process in many semiconductor manufacturing. In the existing process, such as figure 1 As shown, generally by placing the dielectric layer 10 on the substrate 10' and having the contact hole 11 formed therein, heating it to the process temperature in a vacuum chamber, first forming the adhesion barrier layer 12 and the contact hole 11 sequentially. After the seed layer 13 , a tungsten metal layer 14 is deposited and formed in the contact hole 11 . [0003] However, as the miniaturization of devices continues to deepen, the size of the semiconductor interconnection structure becomes smaller and smaller. The tungsten metal lay...

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Problems solved by technology

[0003] However, as the miniaturization of devices continues to deepen, the size of the semiconductor interconnection structure becomes smaller and smaller. The tungsten metal layer is formed by filling the contact hole 11 with a high aspect ratio in one step using the existing chemical vapor deposition process. 14, it is easy to form a hole 15 in the tungsten metal layer 14 in the contact hole 11, the existence of the hole 15 will cause electromigration problems in the subsequent copper process, and will make the metal layer filled in the contact hole The resistance value is large, which leads to a decrease in the reliability of the semiconductor device

In addition, when filling the tungsten metal layer 14 in the contact hole 11, a metal wiring layer must be formed to be connected to the tungsten metal layer 14 to reduce the driving resistance of the device, and forming a metal wiring layer will inevitably occupy the The effective area in the dielectric layer 10, so that the effective area in the dielectric layer 10 becomes smaller

[0004] Since copper has a lower resistivity than tungsten, filling copper in the contact hole 11 can reduce the driving resistance of the device without forming an additional metal wiring layer. However, for figure 1 In terms of the contact hole 11, since the top of the contact hole 11 is right-angled (that is, the sidewall of the contact hole 11 is vertically connected to the upper surface of the dielectric layer 10), before electroplating copper, When the barrier layer and the seed layer are formed, an overhang will be generated at the contact hole 11, so that when the filled copper is electroplated, a hole will be generated inside the filled copper, and the edge area of ​​the contact hole 11 will be filled with copper. The thickness is small, which leads to the electrical failure of the device (EM / SM)

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