Semiconductor device and making method thereof

Abstract

A semiconductor device and a method of manufacturing the same, wherein an underlying metal wiring is formed on a semiconductor substrate 10, and an interlayer insulating film 15 is deposited on the metal wiring. In the abrasion hole 17 formed on the interlayer insulating film 15, an interposer 21 composed of a titanium film 18, a titanium nitride film 19, and a tungsten film 20 is filled. The crystal plane of the tungsten film 20 is oriented on the (110) plane. The end point of the CMP process performed on the second metal film can be accurately detected.

Description

technical field [0001] The present invention relates to a semiconductor device and its manufacturing method, in particular to a semiconductor device in which a contact hole or a via hole is filled with a tungsten film to form an insert and its manufacturing method. Background technique [0002] Conventionally, a plug made of tungsten (tungsten plug) is used to connect the lower layer wiring and the upper layer wiring of a semiconductor integrated circuit. An adhesion layer composed of a titanium film, a titanium nitride film, etc. is deposited on the bottom surface, the wall surface, and the interlayer insulating film of the via hole formed on the interlayer insulating film, and then a tungsten film is deposited by CVD, and then , using CMP (Chemical Mechanical Polishing) method to remove excess portions existing on the interlayer insulating film of the adhesion layer and the titanium film, thereby forming a tungsten plug. [0003] When forming tungsten inserts, a problem t...

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Problems solved by technology

[0003] When forming a tungsten insert, the problem that needs special attention is whether to correctly control the end point of the CMP process when removing the excess portion existing on the interlayer insulating film of the adhesion layer and the titanium film by the CMP method

[0004] When the end point of the CMP process for the tungsten film cannot be detected with high precision, the following problems will arise: that is, the contact resistance of the tungsten insert is significantly increased due to excessive polishing, or the adjacent tungsten is damaged due to insufficient polishing. Plugins are shorting each other

[0006] However, the above-mentioned conventional CMP method has the following problem: that is, since the time when the interlayer insulating film is exposed is regarded as the polishing end point, it is easy to cause excessive polishing.

[0008] However, the current problem is that it is impossible to accurately detect the end point of the CMP process on the tungsten film

exist Figure 8 In the case shown in (a), since the rotational torque increases sharply, it can be correctly detected that the polished film changes from a tungsten film to an adherent layer; Figure 8 In the case shown in (b), since the change in the rotational torque is small, it is impossible to accurately detect the change of the film to be polished from the tungsten film to the adhesion layer, that is, it is impossible to accurately detect the CMP process performed on the tungsten film. the end of

[0010] If the end point of the CMP process on the tungsten film cannot be accurately detected, the amount of polishing on the tungsten film will vary greatly, resulting in either remaining polishing of the tungsten film or forming a cut on the surface of the tungsten film.

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