KR20050105831A - Method for fabricating semiconductor device - Google Patents

Abstract

The present invention adjusts the twist angle in the ion implantation process for source / drain formation so that the source / drain is formed symmetrically in the left and right directions of the word line, thereby providing a word line. A method of manufacturing a semiconductor device capable of improving the on / off characteristic of the present invention.

In the method of manufacturing a semiconductor device according to the present invention, the step of providing a wafer in which the word line is parallel to the flat zone, transferring the wafer into the sheet-type equipment, and ion implanting the wafer at a twist angle of 0 ° Forming a source / drain symmetrical to the left and right directions of the word line.

Description

Manufacturing method of semiconductor device {METHOD FOR FABRICATING SEMICONDUCTOR DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for manufacturing a semiconductor device, and more particularly, by adjusting a twist angle in an ion implantation process for source / drain formation. The present invention relates to a semiconductor device manufacturing method capable of improving the on / off characteristics of a word line by forming symmetrically in the left and right directions.

In the ion implantation process for controlling the threshold voltage and the ion implantation process for forming the source / drain in the well forming process of semiconductor devices, when a silicon wafer in the (100) direction is used, channeling occurs unevenly on the entire surface of the wafer. In order to prevent the phenomenon, a twist ion implantation method is used along with a tilt ion implantation method.

1 is a view for explaining a problem according to the prior art, it is shown that when the source / drain junction ion implantation using a twist angle of 22 °, the source / drain is asymmetrical formed by the occurrence of irregular scattering (scattring). In Fig. 1, reference numeral 1 denotes an active region, reference numeral 2 denotes a word line, and reference numeral a denotes an asymmetric source / drain.

In general, in the related art, the word line of the semiconductor device is formed in a direction perpendicular to or parallel to the flat zone of the wafer. In the case of source / drain ion implantation that proceeds after the word line is formed, FIG. As shown in Fig. 1, when the improper use of the twist angle causes the word line 92 to be distorted due to irregular scattering in the sidewall direction of the word line 2 during the ion implantation process performed by the beam scan method. The ion implantation occurs deeper only in the direction. As a result, the source / drain is formed asymmetrically. In this case, the threshold voltage of the word line is shifted and the on / off characteristic is deteriorated, and the flash drop and tWR (write rrecovery) caused by the deepening of the hot carrier are worsened. There is a problem that the time characteristics become worse and adversely affect the yield improvement.

Accordingly, in order to solve the above problem, an object of the present invention is to adjust the twist angle in the ion implantation process for forming the source / drain when the silicon wafer in the 100 direction is used, thereby forming the source / drain symmetrically, thereby making the word line To provide a method of manufacturing a semiconductor device that can improve the on / off characteristics of.

In order to achieve the above object, the method of manufacturing a semiconductor device according to the present invention comprises the steps of providing a wafer in which the word line is parallel to the flat zone, and transfer the wafer into the sheet-type equipment, and then the twist angle to the wafer to 0 ° Performing ion implantation to form a source / drain symmetrical to the left and right directions of the word line. Prior to the ion implantation process, a step of forming a buffer film on the word line is added.

In the ion implantation step, the tilt angle is used at 0 ° to 9 °.

In the ion implantation step, the dose is 1.0E12 (ions / cm 2) to 5.0E13 (ions / cm 2), and one of 31 P, 75 As and 122 Sb is used as the dopant.

The ion implantation process proceeds by dividing the rotation twice, four times, eight times, and sixteen times.

The method of manufacturing a semiconductor device according to the present invention includes the steps of providing a wafer in which the word line is parallel to the flat zone, transferring the wafer into a batch apparatus, and ion implanting the wafer at a twist angle of 53 to 63 °. Forming a source / drain symmetrical to the left and right directions of the word line.

The method of manufacturing a semiconductor device according to the present invention includes the steps of providing a wafer whose word line is perpendicular to the flat zone, transferring the wafer into a sheet type equipment, and ion implanting the wafer at a twist angle of 90 °. And forming a source / drain symmetrical in the left and right directions of the word line.

The method of manufacturing a semiconductor device according to the present invention includes the steps of providing a wafer in which the word line is perpendicular to the flat zone, transferring the wafer into a batch type equipment, and then proceeding a twist angle to the wafer at 0 to 63 °. Forming a source / drain symmetric in the left and right direction of the.

(Example)

Hereinafter, a method of manufacturing a semiconductor device according to the present invention will be described with reference to the accompanying drawings.

According to the present invention, in the case of a semiconductor device using a silicon wafer in a 100 direction, an asymmetrical source / generated by applying the twist angle applied when the tilt ion implantation is performed to avoid channeling also in the ion implantation for source / drain junction formation. In order to improve the drain junction, by adjusting the twist angle to form a symmetrical source / drain junction, the threshold voltages of the reverse mode and the forward mode are the same to improve on / off characteristics of the word line. Can be improved.

2 is a view for explaining an ion implantation method of a semiconductor device according to an embodiment of the present invention.

3 and 4 are process cross-sectional views illustrating the ion implantation process, in which FIG. 3 illustrates a case where ion implantation proceeds without a buffer film, and FIG. 4 illustrates a case where ion implantation proceeds using a buffer film.

In the method of manufacturing a semiconductor device according to an embodiment of the present invention, as shown in FIG. 2, first, a wafer 10 having an active region 11 and a word line 13 is provided. In this case, the word line 13 is arranged in a direction parallel to the flat zone 10a of the wafer 10.

Subsequently, the wafer 10 is transferred into a sheet type equipment (not shown), and then ion implanted into the wafer with a twist angle of 0 ° so that source / drain symmetrical in the left and right directions of the word line 13 is formed. b) is formed. Here, in the source / drain (b), irregular scattering in the sidewall direction is removed during the beam scan.

In this case, before the ion implantation process, as shown in FIG. 4, the buffer layer 14 is formed on the word line 13 to have a thickness of 1000 μm or less, and then ion implantation is performed using the buffer layer 14. Alternatively, as shown in FIG. 3, the ion implantation process may be performed without a buffer film. Here, in the case of ion implantation without using a buffer film, the dose is 1.0E12 (ions / cm 2) to 5.0E13 (ions / cm 2), and 31 P, 75 As and 122 Sb are used as dopants.

In both of these cases, ion implantation proceeds in a uniform beam scan without scattering on the side of the word line 13.

In the ion implantation process, the tilt angle is 0 ° to 9 °, and the rotation is divided into 2, 4, 8, and 16 cycles, respectively.

On the other hand, when the wafer is a batch type device (not shown), rather than a single sheet type device, ion implantation is performed at 53 to 63 ° with a twist angle to the wafer to form a source / drain symmetrical in the left and right directions of the word line. Form.

5 is a view for explaining an ion implantation method of a semiconductor device according to another embodiment of the present invention.

According to the ion implantation method of the semiconductor device according to another embodiment of the present invention, as shown in FIG. 5, the word line 23 provides a wafer 20 perpendicular to the flat zone 20a. Subsequently, the wafer 20 is transferred into a sheet type equipment (not shown), and ion implantation is performed at 90 ° to the twist angle of the wafer 20 so that the source is symmetrical to the left and right directions of the word line 23. / Drain (c) is formed. At this time, the source / drain (c) is eliminated irregular scattering in the side wall direction during the beam scan.

In this case, the ion implantation process may be performed without a buffer film (not shown), or may be performed using a buffer film, as in an embodiment of the present invention. Here, in the case of ion implantation without using a buffer film, the dose is 1.0E12 (ions / cm 2) to 5.0E13 (ions / cm 2), and 31 P, 75 As and 122 Sb are used as dopants. In both cases, ion implantation proceeds with uniform beam scanning without scattering on the side of the word line 23.

In addition, the ion implantation process may use a tilt angle depending on the purpose during the ion implantation process, preferably, the tilt angle is used at 0 ° ~ 9 °.

In addition, wafer rotation may be performed to improve source / drain uniformity, and the wafer rotation is divided into two, four, eight, and sixteen cycles, respectively. In this case, when the rotation is performed twice, the dose amount at each rotation is 1/2 of the total dose, and when the rotation is performed 4 times, the dose is 1/4 of the total dose. . Similarly, if the rotation is progressed 8 times, the process proceeds to 1/8 and if the rotation is progressed 16 times, the process proceeds to 1/16.

On the other hand, when the batch type equipment is applied instead of the sheet type equipment, the twist angle is advanced to 0 ~ 63 ° to form a source / drain symmetrical in the left and right directions of the word line.

As described above, the present invention adjusts the twist angle during the source / drain ion implantation process, thereby eliminating irregular beam scattering that may occur in the wordline sidewall during the ion implantation beam scan to form a symmetrical source / drain. can do.

Therefore, the present invention can reduce the on-off threshold voltage fluctuation of the word line for the reverse mode and the forward mode, thereby improving on / off characteristics, and also improving hot carrier characteristics and refresh characteristics to increase yield.

In addition, this invention can be implemented in various changes within the range which does not deviate from the summary.

1 is a view for explaining a problem according to the prior art.

2 is a view for explaining an ion implantation method of a semiconductor device according to an embodiment of the present invention.

3 and 4 is a cross-sectional view showing the ion implantation process.

5 is a view for explaining an ion implantation method of a semiconductor device according to another embodiment of the present invention.

Claims (8)

Providing a wafer whose wordline is parallel to the flat zone, And transferring the wafer into the sheet type equipment, and implanting a twist angle at 0 ° into the wafer to form source / drain symmetrical in the left and right directions of the word line. Manufacturing method. The method of claim 1, further comprising forming a buffer layer on the word line before the ion implantation process. The method of claim 1, wherein the ion implantation step uses a tilt angle of 0 ° to 9 °. The method of claim 1, wherein the ion implantation step is a dose of 1.0E11 (ions / ㎠) ~ 5.0E13 (ions / ㎠), and as a dopant, any one of 31P, 75As and 122Sb is used. A method of manufacturing a semiconductor device. The method of claim 1, wherein the ion implantation process is performed by dividing the rotation twice, four times, eight times, and sixteen times. Providing a wafer whose wordline is parallel to the flat zone, Transferring the wafer into a batch apparatus, and ion implanting the wafer at a twist angle of 53 ° to 63 ° to form a source / drain symmetrical to the left and right directions of the word line. Method of manufacturing a semiconductor device. Providing a wafer where the wordline is perpendicular to the flat zone, And transferring the wafer into the sheet type equipment, and implanting a twist angle at 90 ° into the wafer to form source / drain symmetrical to the left and right directions of the word line. Manufacturing method. Providing a wafer where the wordline is perpendicular to the flat zone, Transferring the wafer into a batch device, and then forming a source / drain symmetrical in the left and right directions of the word line by moving the twist angle from 0 ° to 63 ° on the wafer. Manufacturing method.