Silicon nitride gap filling layer and method for forming same

Abstract

The invention relates to a method for forming a packing layer in the clearance of silicon nitride, and the method comprises the following steps: firstly, a former multistage forming process is carriedout to form a stacking film layer on a substrate, thus forming a dense film, and then, a later single stage deposition process is carried out to form a top layer on the stacking film layer, thus forming a loose film, wherein, the thickness of the top layer accounts for more than 10 percent of the total thickness of the packing layer in the clearance of silicon nitride.

Description

technical field [0001] The present invention relates to a semiconductor gap filling layer and its forming method, and in particular to a silicon nitride gap filling layer and its forming method. Background technique [0002] With the development of electronic equipment such as communication technology, the operation speed of transistors is getting faster and faster. However, due to the limitation of the moving speed of electrons and holes in the silicon channel, the application range of the transistor is also limited. [0003] Using the control of mechanical-stress in the channel to change the moving speed of electrons and holes in the channel is a method that can overcome the limitation caused by the shrinkage of the device. [0004] It is known that a method of using silicon nitride as a contact etching stop layer (contact etching stop layer, CESL) to generate strain (Strain) to affect the driving current and ion gain (IonGain) of the transistor to improve the performance...

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Problems solved by technology

[0007] For increasing the thickness of the contact etch stop layer, please refer to figure 1 , due to the insufficient gap-fill (Gap-Fill) ability of the excessively thick silicon nitride layer 102 and the subsequently deposited dielectric layer 104, it is easy to generate gaps (seam) or holes (void) 100, such as figure 1 As shown, therefore, it will cause the problem of subsequent contact etching residue, or cause the short circuit problem between the contact window and the contact window or between the contact window and the gate.

On the other hand, if the aging process is performed after the deposition process in order to further increase the stress of the thick silicon nitride layer, the problem of tearing of the silicon nitride layer will be caused due to the excessive thickness.

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