KR100439099B1 - Method for exposing electron beam of semiconductor device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for exposing an electron beam of a semiconductor device. In particular, a patterned electron beam having a desired shape is formed by using a semiconductor substrate patterned with an n-type active region and a p-type active region in a desired shape as an exposure mask. Since the electron beam patterned in the desired shape is transferred to the photoresist film and the photoresist film is patterned at a time, the time required for electron beam lithography is shortened, and thus electron beam lithography can be used in the device formation process, thereby improving integration of devices.

Description

Method for exposing electron beam of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for exposing an electron beam of a semiconductor device. In particular, a patterned electron beam having a desired shape is formed by using a semiconductor substrate patterned with n-type active region and p-type active region as a mask to form a patterned electron beam. The present invention relates to an electron beam exposure method of a semiconductor device for improving integration.

The technique of patterning the photoresist using electron beams has better resolution than optical lithography.

1 is a perspective view showing a conventional electron beam exposure apparatus.

Referring to FIG. 1, an electron gun 11, a mask stage 12, and a wafer stage 13 are included. The electron gun 11 emits an electron beam EB.

The mask stage 12 seats the exposure mask EM1, and the wafer stage 13 seats the wafer W.

The electron beam emitted from the electron gun 11 is scanned onto the exposure mask EM1. The wafer W is exposed to an electron beam that has passed through the exposure mask EM1.

The electron beam exposure apparatus also includes a first optical system 14 and a second optical system 15.

The first optical system 14 deflects the electron beam emitted from the electron gun 11 in the plane X and Y directions to change the scanned position of the electron beam with respect to the exposure mask EM1 on the mask stage 12.

The second optical system 15 transmits the electron beam passing through the exposure mask EM1 in the plane X and Y directions so as to change the scanned position of the electron beam with respect to the surface of the wafer W on the wafer stage 13. Deflect.

The first and second optical systems 14, 15 are controlled by a controller 16.

The mask stage 12 and the wafer stage 13 are provided with stage drivers 17, 18 controlled by the control device 16.

The stage drivers 17 and 18 change the planar positions of the exposure mask EM1 and the wafer W, respectively.

The control device 16 is connected to a memory 19. The controller 16 reads the addresses from the memory 19 to control the first and second optical systems 14, 15 and the stages 12, 13.

The above-described technique of patterning a photoresist film using an electron beam does not develop an exposure mask that can pattern an electron beam having a predetermined area into a desired shape, and thus, connects a computer having a desired pattern to the electron beam emission equipment, and then lines width to be patterned. Since the photosensitive film is patterned by scanning electron beams having a smaller area while sequentially moving in accordance with a computer command, there is a problem in that it takes a long time to be difficult to use in manufacturing a semiconductor chip.

The present invention has been made in order to solve the above problems, and by using a semiconductor substrate patterned with a n-type active region and a p-type active region as a mask to form a patterned electron beam of a desired shape is patterned into the desired shape SUMMARY OF THE INVENTION An object of the present invention is to provide an electron beam exposure method of a semiconductor device in which an electron beam is transferred to a photosensitive film to pattern the photosensitive film at a time.

1 is a perspective view showing a conventional electron beam exposure apparatus.

2 is a cross-sectional view illustrating the directions of a primary electron beam incident from the outside and a secondary electron beam or backscattered electron beam emitted from a subject, respectively.

3A and 3B are perspective views illustrating a method of forming an exposure mask used in an electron beam exposure process of a semiconductor device according to an embodiment of the present invention.

Fig. 4 is a layout showing the disposed shapes of each of the p-type / n-type active region and the tungsten plug.

5 is a photograph showing the emission amount of the secondary electron beam or the backscattered electron beam of FIG.

6A to 6C are circuit diagrams showing a state in which there is no bias, a state in which forward bias is applied, and a state in which reverse bias is applied to a structure in which n-type and p-type junctions are respectively.

7 is a cross-sectional view showing the emission of a secondary electron beam or a backscattered electron beam in a structure each including an n-type / p-type active region.

<Explanation of symbols for main parts of drawing>

11 electron gun 12 mask stage

13 wafer stage 14 first optical system

15: second optical system 16: control device

17,18: stage driver 19: memory

31: subject 33,61: primary electron beam

35 secondary electron beam 37,63 backscattered electron beam

41: semiconductor substrate 43: p well

45: n well 47: n-type active region

49: p-type active region 51: oxide film

53: Tungsten Plug

In the electron beam exposure method of the semiconductor device of the present invention, an n-type active region and a p-type active region are separated from each other and patterned on a semiconductor substrate having p wells and n wells, and require more electron beams than the n-type active regions. Patterning a p-type active region on the substrate, forming an insulating film having contact holes formed on the n-type active region and the p-type active region on the entire surface thereof, and forming a plug to fill the contact hole; And injecting a primary electron beam into the structure to emit an electron beam patterned in the same form as the contact hole through the plug, and transferring the electron beam to an exposure target layer to pattern the exposure target layer. It is done.

2 is a cross-sectional view illustrating the directions of a primary electron beam incident from the outside and a secondary electron beam or backscattered electron beam emitted from a subject, respectively.

Referring to FIG. 2, when the primary electron beam 33 is incident on the subject 31 such as a circuit from the outside, the secondary electron beam 35 or the backscattered electron beam 37 is emitted from the subject 31.

The secondary electron beam 35 has a low energy of 50 eV or less as an electron generated within a range of about 300 mW on the surface of the subject 31. The amount of the secondary electron beams 35 depends on the surface shape of the subject 31 and the storage state of the surface.

The back scattering electron beam 37 has energy of 50 eV or more as electrons emitted at a depth of about 1/3 of the maximum depth at which the incident primary electron beam 33 reacts with the subject 31. The amount of the backscattered electron beam 37 is controlled by the power storage state inside the subject 31.

In general, when the amount and energy of the primary electron beam 33 become larger, the amount of the primary electron beam penetrating to the inside of the subject 31 increases, so that the backscattered electron beam 37 is more relative to the secondary electron beam 35. Will increase.

The principle of the present invention is an invention for forming an exposure mask capable of patterning an electron beam into a desired shape by using a secondary electron beam or a backscattered electron beam emitted from a subject by the incident first electron beam as described above.

Hereinafter, an electron beam exposure method of a semiconductor device according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3A and 3B are perspective views illustrating a method of forming an exposure mask used in an electron beam exposure process of a semiconductor device according to an embodiment of the present invention.

Referring to FIG. 3A, the n-type active region 47 and the p-type active region 49 are formed on the semiconductor substrate 41 having the p well 43 and the n well 45, but there are few electrons. The region to be patterned is patterned into the n-type active region 47 and the region where a lot of electrons is to be patterned into the p-type active region 49.

After the oxide film 51 is formed on the entire surface, the oxide film 51 on the n-type active region 47 and the p-type active region 49 is etched. In this case, the oxide layer 51 serves as a separator between the n-type active region 47 and the p-type active region 49.

Next, a tungsten plug 53 is formed on the n-type active region 47 and the p-type active region 49 exposed between the oxide layers 51. At this time, the difference in the density of electrons emitted from the n-type active region 47 and the p-type active region 49 by the tungsten plug 53 is maintained and is activated by the primary energy beam of strong energy incident from the outside. Prevents the area from being tampered with.

Thereafter, a primary electron beam 61 having a constant density is incident on the structure.

Referring to FIG. 3B, 2 having the same density difference as that of the pattern of the semiconductor substrate 41 by the incident primary electron beam 61 according to the emission amount of the secondary electron beam or the backscattered electron beam 63. The secondary electron beam or backscattered electron beams 63 can be emitted to obtain an electron beam patterned in the desired form of a line / space.

In addition, a method of obtaining a patterned electron beam in the form of a contact hole using the present invention is as follows.

FIG. 4 is a layout diagram showing the arrangement of each of the p-type / n-type active region and the tungsten plug, and FIG. 5 is a photograph showing the emission amount of the secondary electron beam or the backscattered electron beam of FIG. 4.

Referring to FIG. 4, the n-type active region 47 and the p-type active region 49 are formed on the semiconductor substrate 41 having the p well 43 and the n well 45, but there are few electrons. The region to be patterned is patterned into the n-type active region 47 and the region where a lot of electrons is to be patterned into the p-type active region 49.

After the oxide film 51 is formed on the entire surface, a contact hole is formed by etching the oxide film 51 above the n-type active region 47 and the p-type active region 49. In this case, the oxide layer 51 serves as a separator between the n-type active region 47 and the p-type active region 49.

Next, a tungsten plug 53 filling the contact hole is formed. At this time, the difference in the density of electrons emitted from the n-type active region 47 and the p-type active region 49 by the tungsten plug 53 is maintained and is activated by the primary energy beam of strong energy incident from the outside. Prevents the area from being tampered with.

Subsequently, when the primary electron beam 61 having a constant density is incident on the structure, as shown in FIG. 5, the brightness difference of each region is varied according to the emission amount of the secondary electron beam or the back scattering electron beam 63. Secondary electron beams or backscattered electron beams 63 having a density difference of the same shape as the pattern shape of the semiconductor substrate 41 are emitted by the difference electron beam 61 to obtain an electron beam patterned into a desired shape of a contact hole.

In this case, a method of increasing the density difference between the electron beams may include increasing the amount and energy of the primary electron beams 61 to increase the amount of emitted backscattered electron beams or doubling the density difference using multiple masks. There is a way to.

The method using the plurality of masks concentrates and accelerates the patterned electron beam using a first mask and then enters a second mask patterned in the same shape, wherein the low density electron beam emitted from the n-type active region is The electron beam emitted from the second mask is adjusted to be incident on the n-type active region of the second mask and is emitted from the p-type active region to be incident on the p-type active region of the second mask. The density difference can be doubled while maintaining the same pattern of density as the electron beam emitted from it.

6A to 6C are circuit diagrams illustrating a state where there is no bias, a state of applying a forward bias, and a state of applying a reverse bias to structures in which n-type and p-type junctions are formed, and FIG. 7 is n-type / p-type active. A cross-sectional view showing the emission of a secondary electron beam or a backscattered electron beam in a structure each containing a region.

6A and 7, when the primary electron beam 33 is introduced into the active region through the tungsten plug 53, the backscattered electrons are generated inside the active region to cause isotropic diffusion.

At this time, since the p well 43 or the n well 45 has a large electrical capacity, the potential does not change even when electrons are introduced from the outside, but the n-type active region 47 or the p-type active region 49 has a large electrical capacitance. Because of the small size, the potential changes easily when electrons are introduced from the outside. In addition, rectifier effects occur at the interface between the well-doped active regions and the wells.

6B and 7, when the backscattered electrons generated in the structure including the n-type active region 47 move in the direction of the p well 43 in the n-type active region 47, an NP-coupled rectifier The electrons move easily into the p well 43 having a large electrical capacity since it causes an effect of applying a forward voltage to the p well 43.

6C and 7, on the contrary, if the backscattered electrons generated in the structure including the p-type active region 49 move in the direction of the n well 45 from the p-type active region 49, NP Electrodes do not flow into the n well 45 but accumulate in the p-type active region 49 because it causes an effect of applying a reverse voltage to the coupling rectifier.

As a result, electrons move easily into the p well 43 in the structure including the n-type active region 47, and electrons in the structure including the p-type active region 49 form the p-type active region ( As it accumulates in 49, more secondary electron beams or backscattered electron beams 63 are emitted from the structure comprising the p-type active region 49 than the structure comprising the n-type active region 47.

As described above, in the present invention, since an exposure mask capable of patterning the electron beam in a desired shape is formed, the electron beam emission equipment using the exposure mask is not required to be connected to the electron beam emission equipment without a computer having a desired pattern input as in the prior art. The photosensitive film may be patterned at one time by transferring the electron beam patterned in the desired shape to the photosensitive film.

The electron beam exposure method of the semiconductor device of the present invention forms a patterned electron beam of a desired shape by using a semiconductor substrate patterned with a n-type active region and a p-type active region as a mask to form a patterned electron beam. Since the photoresist film is transferred to the photoresist film and the photoresist film is temporarily patterned, the time required for electron beam lithography is shortened, and thus, electron beam lithography can be used in the device formation process, thereby improving the integration of the device.

Claims (2)

delete patterning the n-type active region and the p-type active region on the semiconductor substrate including the p well and the n well, wherein the p-type active region is patterned in a region requiring more electron beams than the n-type active region; Forming an insulating film having a contact hole formed over the n-type active region and the p-type active region on a front surface thereof; Forming a plug to fill the contact hole; Injecting a primary electron beam into the structure and emitting an electron beam patterned in the same shape as the contact hole through the plug; Transferring the electron beam to the exposure target layer to pattern the exposure target layer.