Manufacturing method of semiconductor device

Details Manufacturing method of semiconductor device Manufacturing method of semiconductor device

1999-11-15

2001-05-15

Nelms, David (Department: 2818)

Semiconductor device manufacturing: process

Making field effect device having pair of active regions...

Having insulated gate

C438S291000

Reexamination Certificate

active

06232189

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing semiconductor devices, and more particularly, to a method of manufacturing semiconductor devices having an effective channel of a target length.
2. Description of the Related Art
As the integration of semiconductor devices increases, their size becomes smaller. As a result, techniques for finely processing the same have been developed in the manufacturing process of semiconductor devices. Here, a photolithography process is a basic process for manufacturing semiconductor devices. The photolithography process greatly depends on materials or devices. In particular, when the photolithography process for forming a gate electrode of a transistor is performed, the length of the gate electrode can change by tens of nanometers in accordance with process conditions.
In the conventional art, a gate electrode composed of a gate insulating layer and a gate conductive layer is formed on a semiconductor substrate, and then a lightly-doped source and drain are formed by implantation using the gate electrode as a mask under conditions determined before manufacturing of the semiconductor device. When implantation for forming a source and drain is performed, implanted dopants are laterally diffused to the down-direction of the gate electrode. As a result, the length of the effective channel which is defined by the source and drain is reduced. Thus, the length of the channel which is formed under the gate electrode is determined by the length of the gate electrode and the lateral diffusion length of implanted dopants.
However, when the gate electrode is formed by photolithography, the length of the gate electrode typically varies in the order tens of nanometers depending on the process conditions. Even though the length of the gate electrode, the source and drain are implanted in accordance with implantation conditions which are determined before the process, so that the lateral diffusion length of implanted dopants are constant. Thus, the length of the effective channel formed under the gate electrode is proportional to the length of the gate electrode. That is, when devices are manufactured by conventional methods of semiconductor devices manufacturing, the length of the gate electrode is changed by conditions of the photolithography process and thus the length of the effective channel is changed.
However, when the length of the formed gate electrode is shorter than a target length, the length of the effective channel formed under the gate electrode becomes short to thereby deteriorate the yield rate. When the length of the formed gate electrode is longer than that of the target gate electrode, the length of the effective channel becomes long, thereby deteriorating the operational speed of the device.
SUMMARY OF THE INVENTION
To solve the above problems, it is an objective of the present invention to provide a manufacturing method of semiconductor devices by which an effective channel of a target length is formed even though the length of the gate electrode varies depending on a change in process conditions, to thereby suppress reduction in the yield or operational speeds of devices.
Accordingly, to achieve the above objective, by the manufacturing method of semiconductor devices, a semiconductor substrate where a gate electrode is formed is provided. Then, two or more measurement points where densities of the gate pattern are different are set, and then the lengths of the gate electrodes in the two or more measurement points are measured. A gate electrode length as a reference for determining the implantation conditions is selected from the lengths of two or more measured gate electrodes. At this time, preferably, the length of the gate electrode having the smallest margin of the implantation process is selected from the two or more measured gate electrode lengths. Then, a lateral diffusion distance is calculated using the measured length of the gate electrode and a length of a target effective channel. Subsequently, implantation conditions for the calculated lateral diffusion distance are determined with reference to data of the relationship between the change of the ion implantation conditions and the lateral diffusion distance. Ion implantation is performed in accordance with the determined ion implantation conditions to thereby form the source and drain which define a channel having the target length. At this time, preferably, the ion implantation conditions are implantation energy, implantation angle and the implantation dosage.
According to the present invention, the gate electrode is formed, and then the length of the gate electrode is measured and implantation conditions for forming the source and drain are determined using the measured length of the gate electrode, so that even though the length of the gate electrode varies, a source and drain defining an effective channel having the constant target lengths can be formed.


REFERENCES:
patent: 5270226 (1993-12-01), Hori et al.
patent: 5759901 (1998-06-01), Loh et al.
patent: 5804496 (1998-09-01), Duane
patent: 6080630 (2000-06-01), Milic-Strkalj et al.
patent: 0123456 A2 (2000-01-01), None

Affiliated with

Also associated with

Rating

Manufacturing method of semiconductor device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Manufacturing method of semiconductor device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Manufacturing method of semiconductor device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2476154