KR19980030832A - Manufacturing method of semiconductor device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for forming a well of a semiconductor device in which a two-well well is formed by a single mask process, thereby reducing process steps and improving production yield. Forming an oxide film on the substrate; Implanting a second conductivity type impurity opposite to the first conductivity type on the semiconductor substrate; Forming a photoresist pattern on the oxide film; Implanting a first conductivity type impurity using the photosensitive film as a mask; Removing the photoresist pattern; Performing drive-in on the first and second conductivity type impurities implanted on the semiconductor substrate to form well regions of the first and second conductivity type; And removing the oxide film, wherein the dose of the second conductivity type impurity is twice the dose of the first conductivity type impurity, and the first conductivity type impurity is a semiconductor without a mask pattern. It is characterized in that the ion implantation on the entire surface of the substrate.

Description

Manufacturing method of semiconductor device

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for forming a well of a semiconductor device capable of forming a twin well through a single mask process.

1A to 1D are cross-sectional views for describing a twin well forming method of a conventional semiconductor device.

First, as shown in FIG. 1A, a predetermined oxide film 2 for an ion implantation process is formed on the semiconductor substrate 1, and an ion implantation mask pattern is formed on the P well and the N well thereafter. In order to do this, photolithography forms a pattern of a key mask 3 which acts as a predetermined alignment mask. This key mask 3 is a first mask for forming the two wells.

Subsequently, although not shown, the oxide film 2 in the portion where the well is not formed is etched using the key mask 3, and the key mask 3 is removed by a known method.

As shown in FIG. 1B, the second mask 4 pattern is formed through photolithography on the oxide film 2 that is not etched by the etching process, that is, the portion where the well is to be formed. Then, a P well ion implantation step is performed in which the second mask 4 is used as an ion implantation mask and B is an ion implantation source.

As shown in FIG. 1C, the second mask 2 is removed by a known method, and again the third mask 5 pattern is formed on the oxide film 2 through photolithography. Then, using the third mask 5 as an ion implantation mask, an N well ion implantation process is performed in which P is an ion implantation source.

As shown in FIG. 1D, the third mask 5 is removed in a known manner. Subsequently, a well drive-in process is performed on the ions implanted on the semiconductor substrate 1 through the ion implantation to form regions of the P well 6 and the N well 7, and the oxide film 2 is well-known. When removing the, twin wells of the semiconductor device are formed.

However, in the above-described conventional two-win well forming method, since the mask process has to be performed three times in order to form the P type well and the N type well, the productivity is not significantly reduced and the predetermined mask process is repeated due to the repeated mask process. Defect occurs and there is a problem that the manufacturing yield of the device is lowered.

Accordingly, an object of the present invention is to provide a method for manufacturing a semiconductor device capable of reducing process steps and improving device manufacturing yield by forming a two-well well in one mask process. .

1A to 1D are cross-sectional views illustrating a conventional twin well forming method.

2A to 2C are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

11: semiconductor substrate 12: sacrificial oxide film

13: photosensitive film 14: N well

15: P well

A semiconductor device manufacturing method according to the present invention for achieving the above object comprises the steps of forming an oxide film on a first conductivity type semiconductor substrate; Implanting a second conductivity type impurity opposite to the first conductivity type on the semiconductor substrate; Forming a photoresist pattern on the oxide layer; Implanting first conductivity type impurities using the photoresist as a mask; Removing the photoresist pattern; Performing drive-in on the first and second conductivity type impurities implanted on the semiconductor substrate to form well regions of the first and second conductivity type; And removing the oxide film.

The dose of the second conductivity type impurity may be twice the dose of the first conductivity type impurity, and the first conductivity type impurity is implanted into the entire surface of the semiconductor substrate without a mask pattern. do.

According to the present invention having the above constitution, after the first conductivity type impurity is injected into the entire surface of the semiconductor substrate, the dose amount of the second conductivity type impurity is twice as large as that of the first conductivity type impurity on the semiconductor substrate using a mask pattern. By injecting into, it is possible to form a two-well well in a single mask process.

EXAMPLE

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention.

2A to 2C are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with an embodiment of the present invention.

First, as shown in FIG. 2A, a predetermined sacrificial oxide film 12 for an ion implantation process is formed on the P-type or N-type semiconductor substrate 11. Then, an N well ion implantation process is performed on the entire surface of the semiconductor substrate 11 with P as an ion implantation source.

As shown in FIG. 2B, a photosensitive film 13 is coated on the sacrificial oxide film 12, and a photosensitive film 13 mask pattern for forming a P well is formed through photolithography. Then, a P well ion implantation process is performed in which B is an ion implantation source using the photosensitive film 13 mask pattern as an ion implantation mask. In this case, the P well ion implantation process is performed by making the dose of B about twice as much as the dose of P in order to convert the P region implanted on the entire surface of the semiconductor substrate 11 back to the B region.

Thereafter, although not shown, the lower sacrificial oxide film 12 is etched using the photosensitive film 13 mask so as to provide a predetermined alignment mark later on the semiconductor substrate 11.

As shown in FIG. 2C, the photosensitive film 13 is removed by a known method, and a well drive-in process for ions implanted on the semiconductor substrate 11 is performed. Subsequently, the N well 14 and P well 15 regions are formed by removing the sacrificial oxide film 12 in a known manner. Although not shown in detail in FIG. 2C when the sacrificial oxide layer 12 is etched, a predetermined alignment mark is formed as the semiconductor substrate 11 is partially trenched.

According to the above embodiment, the N well ion implantation process is performed on the entire surface of the semiconductor substrate, and then the P well ion implantation process is performed using the mask pattern, thereby forming the two wells by a single mask process.

Accordingly, it is possible to reduce the process step to suppress the occurrence of defects through a number of processes to improve the production yield of the device, as well as to significantly improve the productivity.

In addition, this invention is not limited to the said Example, It can variously deform and implement within the range which does not deviate from the technical summary of this invention.

As described above, according to the present invention, it is possible to realize a semiconductor device manufacturing method capable of reducing the process steps and improving the production yield of the device.

Claims (7)

Forming an oxide film on the first conductivity type semiconductor substrate; Implanting a second conductivity type impurity opposite to the first conductivity type on the semiconductor substrate; Forming a photoresist pattern on the oxide layer; Implanting first conductivity type impurities using the photoresist as a mask; Removing the photoresist pattern; Performing drive-in on the first and second conductivity type impurities implanted on the semiconductor substrate to form well regions of the first and second conductivity type; And, And removing the oxide film. The method of claim 1, wherein the dose of the second conductivity type impurity is twice the dose of the first conductivity type impurity. The method of claim 1, wherein the first conductivity type impurity is implanted into the entire surface of the semiconductor substrate without a mask pattern. The method of claim 1, wherein the first conductivity type impurity is P. The method of manufacturing a semiconductor device according to claim 1, wherein the second conductivity type impurity is B. The method of claim 1, further comprising etching the oxide film between removing the photoresist pattern and performing the drive-in process. The method of claim 6, wherein the etched oxide film provides a predetermined alignment mark on the semiconductor substrate.