JP3417867B2 - Source wafer for electron beam exposure and semiconductor manufacturing apparatus using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus that realizes ultra-high integration.

[0002]

2. Description of the Related Art The factors that improve the performance of lithography technology are resolution, depth of focus, throughput, and yield.
Is one. The optical lithography technology, which has been overwhelmingly mainstream until now, has excellent characteristics in all four points.
However, 4G is said to be realized after 2002
The minimum processing size required by b-DRAM is 100 [nm],
This area is expected to be disadvantageous in terms of resolution.

On the other hand, the technique using the electron beam or X-ray has been known to be superior to the optical lithography technique in the resolution and the depth of focus, but it has two points of throughput and reliability. It was a long way apart. In other words, a technology that overcomes these two points will become the mainstream lithography technology for the next era. Heretofore, it has been pointed out that electron beams require a long time for the beam to trace the pattern.

Therefore, the tunnel cathode method (R. Ward, J.
Vac.Sci.Technol.16,1830 (1979).) And hot electron cathode method (M.Poppeller, et.al., Appl.Phys.Lett.
73, 2835 (1998).) Was proposed, and it is said that the minimum processing dimension length of 90 [nm] can be realized while significantly improving the throughput. However, all of these methods use a tunnel oxide film, and particularly the latter uses an ultrathin metal film having a high resistance as a wiring, and thus has a drawback of poor reliability. Therefore, it is considered that the yield is adversely affected.

[0005]

DISCLOSURE OF THE INVENTION The present invention is directed to the tunnel cathode method (R. Ward, J. Vac. Sci. Technol. 16, 1830 (197).
9).) And hot electron method (M.Poppeller, et.a
l., Appl.Phys.Lett.73,2835 (1998).) The structure that improves the throughput is left as it is, and the wiring that uses the tunnel oxide film and the ultra-thin metal film that causes the decrease in reliability is deleted. However, it is an object of the present invention to provide a semiconductor manufacturing apparatus that achieves similar effects.

[0006]

According to a first aspect of the present invention, there is provided a vacuum container, a target substrate installation base formed in the vacuum container for installing a target substrate, and the target substrate installation base facing the target substrate installation base. A semiconductor substrate provided in a vacuum container; a first metal film formed on first and second regions of a first surface of the semiconductor substrate facing the target substrate mounting base; A second metal film selectively formed on the first metal film corresponding to the first region of the first surface of the semiconductor substrate, and a second metal film on the opposite side of the first surface of the semiconductor substrate.
And a pn junction or a Schottky junction selectively formed in the second region of the first surface, and a third metal film formed on the first surface of the semiconductor manufacturing apparatus. .

According to a second invention of the present application, the target substrate mounting table includes an electron beam sensor for monitoring an electron beam emitted from the second region, and the first and second electron beam sensors are provided according to an output of the sensor. The semiconductor manufacturing apparatus according to the first invention of the present application, further comprising means for controlling a voltage applied between the third metal film and the third metal film.

A third invention of the present application is the semiconductor substrate, the first metal film formed on the first and second regions of the first surface of the semiconductor substrate, and the first metal film of the first surface. A second metal film selectively formed on the first metal film corresponding to the first region, and a third metal film formed on a second surface of the semiconductor substrate opposite to the first surface. And a pn junction or a Schottky junction selectively formed in the second region of the first surface, which is a source wafer for electron beam exposure. That is, the present invention uses, as an electron beam source, hot carriers generated when a reverse bias is applied to a pn junction or the like having a high carrier concentration.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to Examples. An embodiment of the present invention will be described with reference to FIG.
The target wafer and the source wafer are placed in parallel in the ultra-high vacuum chamber with a separation of 5 [nm]. The method of providing this minute interval is described in M. Poppeller, et. Al., Appl. Phys. L.
ett.73, 2835 (1998). A sapphire ball with a diameter of 5 [nm] may be sandwiched between the target wafer and source wafer mounts. Further, the device
It exists in a uniform magnetic field applied in the vertical direction of the drawing.

In this embodiment, the upper side is a source wafer which is turned upside down, and the lower side is a target wafer.
An aluminum film is applied to the entire back surface of the source wafer except for a matching window. An electrode is provided thereon, and a negative voltage -VR (VR> 0) is applied to the electrode by the electron beam control device. FIG. 2 shows a view of the back surface of the source wafer viewed from the upper side of this sectional view. The alignment marks formed on the target wafer through the alignment windows provided at three locations are seen in a form that matches the marks on the window side. The dotted line on the perimeter is
This is an area for the electron beam sensor provided on the back side of this figure. 4 [nm] on the surface of the source wafer (lower side in this figure)
Is coated with a very thin aluminum film, and a patterned aluminum film including an electron beam sensor region in the outer peripheral portion is further coated thereon. An electrode is provided on the aluminum film, and the electrode is applied with a potential. Use as a base. Thus, the hot electron method (M.Poppeller, et.al., App
L. Phys. Lett. 73, 2835 (1998).), which was one of the drawbacks of the ultra thin aluminum film, could be eliminated.

A p-well (1014 cm −3) was formed on the underlayer of the thick aluminum window formed by the patterning.
An n-diffusion layer (1014 cm-3) is provided, and hot carriers are boiled in the pn junction by adjusting the VR described above. This hot carrier permeates the ultrathin aluminum film and is discharged into a vacuum. In order to strengthen the electron beam, there is a method of further thinning the ultrathin aluminum film or adjusting the impurity concentration of VR or the p-well and the diffusion layer. If there is no oxide film on the ultra-thin aluminum film, a release rate of about 10% should be shown at a thickness of 4 [nm]. It will be about 0.3% due to the influence of the deposited oxide film. This means that the emission rate changes as the electron beam is repeatedly emitted. Actually, the effect of emitted electron interacting with oxygen atom to desorb oxygen atom (G.
GP van Gorkom and AME Hoebrechts, J. Vac,
Sci. Technol. B4, 108 (1986).), And the influence of oxide film growth is small.

However, in order to secure the reliability of the mask for a long period of time, the following device for controlling the electron beam with which the target wafer is irradiated is used. The electron beam emitted from the pn junction provided on the outer peripheral portion of the substrate does not reach the target wafer and is monitored by the electron beam sensor provided on the installation table. The electron beam sensor is connected to the electron beam control device, and the electron beam control device adjusts VR so as to compensate for the resistance changed by the growth of the oxide film deposited on the surface of the ultrathin aluminum film. Thus, the controlled electron beam always reaches the target wafer. If the electron beam becomes weak after a long period of use, the grown oxide film is removed by chemical treatment. Such refreshing of the electron beam window cannot be applied to the tunnel oxide film used in the prior art. The pn junction described above may be a Schottky junction.

In this embodiment, the target wafer has 10
A high voltage of [kV] and a magnetic field parallel to it are applied. By adjusting this electromagnetic field, the focus and intensity of the electron beam that reaches the target wafer can be controlled.

Next, with reference to FIG. 3, a method for conducting the semiconductor manufacturing process without exposing the source wafer used as a mask to the atmosphere will be described. A threshold wall that can be opened / closed by an automatically controlled mechanical device, or a threshold that is set by a window 2
There are two ultra high vacuum chambers UHV1 and UHV2. UH
At V1, the target wafer mounted on the mounting table and the source wafer 1 mounted on the mounting table are positioned in parallel with each other with the sapphire ball. Source wafers 2, 3, ... N used in the next irradiation process are stored in the UHV2. The source wafers 1 and 2 are exchanged by the following procedure. First, the automatically controlled threshold wall is opened. next,
Similarly, the source wafers 1 and 2 mounted on the installation table are exchanged using the arm of the opportunity device which is also automatically controlled. Finally, the threshold wall is closed and valves are used to regulate the atmosphere in UHV1,2. Further, when the target wafer is taken out, the threshold wall is closed and the atmosphere is injected from the valve 1 into the UHV1. When the target wafer is set again, the threshold wall is closed, the target wafer is set again, and after closing the door of the UHV 1, the atmosphere is extracted from the valve 1. The chamber may be filled not only with ultra-high vacuum but also with a rare gas having low chemical reactivity such as argon or helium, or a dry atmosphere containing no oxygen. The usage of the valve 1 for loading / unloading the target wafer is the same as described above.

Next, a method of manufacturing the window for emitting the electron beam described in FIG. 1 will be briefly described. As shown in FIG. 4, first, an aluminum film patterned by a conventional electron beam method is slowly applied over an exposed p + substrate for a long time. Further, as shown in FIG. 5, the diffusion method is performed twice, the p-well and the diffusion layer are formed, and then the CVD method is performed.
Deposit an ultra thin film of aluminum.

Finally, a method of matching will be described. Figure 1
As can be seen in Fig. 2, the through holes of the source wafer are provided with alignment marks on either the front side or the back side of the alignment window filled with a transparent film to prevent the holes from being oxidized and closed. . On the surface of the target wafer, alignment marks are provided with the same size, the same shape, and corresponding orientation as the marks on the source wafer. The back side of the source wafer in FIG. 1 (from the top in FIG. 1) is viewed through the window for the alignment with a microscope, and the alignment mark on the source wafer is looked into. If the alignment is successful, you should see the matching marks from each window as shown in FIG. The number of the matching windows is not particularly specified, and any number may be used as long as it is not one. Another method is to use a light emitting device that is provided in advance at a specified position on the target wafer.
Alternatively, a reflective film can be used.

The aluminum used in this embodiment can be replaced with another kind of metal. Even if the target wafer is on the upper side and the source wafer is on the lower side, the embodiment is essentially the same. The p-well, the impurity concentration of the diffusion layer, the thickness of the ultrathin aluminum film, etc. can be adjusted to such an extent that the effects of the present invention are not substantially impaired.

[0018]

According to the present invention, it is possible to provide a lithographic technique that realizes a resolution of 100 [nm], has a short throughput, and is highly reliable.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an embodiment of the present invention.

FIG. 2 is a view seen from the back side (upper side in FIG. 1) of the source wafer.

FIG. 3 is a view showing a method of exchanging a source wafer and taking a target wafer in and out while controlling the atmosphere in the chamber.

FIG. 4 is a diagram illustrating a method of manufacturing an electron emission window.

FIG. 5 is a diagram illustrating a method of manufacturing an electron emission window.

[Explanation of symbols]

UHV1, UHV2 Ultra high vacuum chamber

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Takagi 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Toshiba Corporation Yokohama office (56) Reference JP-A-1-135022 (JP, A) JP-A 1-134922 (JP, A) JP 63-185025 (JP, A) JP 3-174715 (JP, A) JP 1-162335 (JP, A) JP 47-36975 (JP, A) JP-A-55-15232 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/027 G03F 7/20 504

Claims (3)

(57) [Claims] 1. A vacuum container, a target substrate installation base formed in the vacuum container for installing a target substrate, and a semiconductor substrate provided in the vacuum container facing the target substrate installation base. A first metal film formed on the first and second regions of the first surface of the semiconductor substrate facing the target substrate mounting base, and corresponding to the first region of the first surface. A second metal film selectively formed on the first metal film; a third metal film formed on a second surface of the semiconductor substrate opposite to the first surface; P formed selectively in the second region of the first surface
A semiconductor manufacturing device comprising an n-junction or a Schottky junction. 2. The target substrate installation base is the second substrate.
An electron beam sensor for monitoring an electron beam emitted from the region, and means for controlling a voltage applied between the first and second metal films and the third metal film according to an output of the sensor. The semiconductor manufacturing apparatus according to claim 1, further comprising: 3. A semiconductor substrate, a first metal film formed on first and second regions of a first surface of the semiconductor substrate, and a first metal film corresponding to the first region of the first surface. A second metal film selectively formed on the first metal film, and a third metal film formed on a second surface of the semiconductor substrate opposite to the first surface, P formed selectively in the second region of the first surface
A source wafer for electron beam exposure, comprising an n-junction or a Schottky junction.