Method of forming a poly silicon resistor device and semiconductor device

Abstract

The present disclosure provides a poly resistor on a semiconductor device and a method of fabricating the same. In an embodiment, a poly silicon resistor device is formed by providing a substrate having a first region and a second region. A dummy gate stack is formed on the substrate in the first region, wherein the dummy gate stack has a dummy gate stack thickness extending above the substrate. A poly silicon resister is formed on the substrate in the second region, wherein the poly silicon resistor has a poly silicon resistor thickness extending above the substrate a distance which is less than the dummy gate stack thickness. A dopant is implanted into the substrate in the first region thereby forming a source region and a drain region in the first region of the substrate. The dopant is also implanted into the poly silicon resistor. An inter-level dielectric (ILD) layer is formed on the substrate over the dummy gate stack and also over the poly silicon resistor. The ILD layer is planarized, thereby exposing the dummy gate stack and leaving a portion of the ILD layer over the poly silicon resistor. The dummy gate stack is replaced with a high k metal gate while using the portion of the ILD layer over the poly silicon resistor as a mask to protect the poly silicon resistor during replacement of the dummy gate stack with the high k metal gate.

Description

technical field [0001] The invention relates to a semiconductor device and its forming method, in particular to a polysilicon resistance device and its forming method. Background technique [0002] Polysilicon resistors have been widely used in the design of integrated circuits (ICs). Likewise, due to technology node scaling, high k dielectric materials and metals are used to form gate stacks of semiconductor devices, such as metal oxide semiconductor field effect transistors (MOSFETs). However, there are many problems in combining polysilicon resistors with metal gates of MOSFETs on a single integrated circuit chip. One solution is to use dummy gates when forming polysilicon resistors. A gate replacement process is then used to remove the dummy gate. However, the etch process can damage or recess the formed polysilicon resistors, causing the polysilicon resistors to deviate from the originally designed target resistors and causing other problems. A solution to this prob...

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Problems solved by technology

However, this requires additional hard mask deposition, thereby increasing the complexity and cost of the manufacturing process

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