JPS58123717A - Preparation of semiconductor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technology of the Invention Bonno The present invention uses an electron beam to irradiate a polycrystalline semiconductor layer deposited on an insulating film to form a single crystal. Enables single crystallization over the entire range.

The present invention relates to a method for manufacturing a semiconductor device.

(2nd technology background Polycrystalline silicon gold grown on single crystal silicon.

A technique of annealing the wafer to form a single crystal by irradiating the wafer with an electron beam has recently been put into practical use in the manufacture of semiconductor devices. This technology has excellent features as a rounding technology for building three-dimensional KIC circuits.

That is, CVI is formed on a silicon substrate via III oxide.
) When a silicon crystal is grown by a method such as the above method, the crystal inevitably becomes a polycrystalline layer. If this layer were to be made into a single crystal by placing the wafer in an electric furnace, the silicon substrate itself would melt.

This method cannot be adopted. However, by using an electron beam that can locally heat the substrate, it is possible to crystallize the grown polycrystals* without melting the substrate.

On the other hand, with the recent progress in ultra-LSI technology, the area of semiconductor chips has become larger and larger, and therefore the technology to obtain a single crystal layer over a large area has become an important issue in the manufacturing process.

(3) Problems with the Prior Art In the conventional electron beam annealing method, the temperature distribution at the spot of the electron beam is a so-called Gaussian distribution, which is high in the center and low in the periphery.

On the other hand, since the single crystallization of the polycrystalline layer occurs from the low temperature region of the beam spot, in the case of a conventional beam spot, the single crystal layer grows from the periphery of the beam as it cools down. I had it. For this reason, it had the disadvantage that a single crystal layer could only grow locally.

That is, in FIG. 1, 5
On a polycrystalline silicon substrate 1 grown via iOii,
When scanning an electron beam spot 2 with a diameter of 30 to 1100 nm with a current value of 1 to IQmA and a power of 20 to 200 W, the temperature at the center of the beam spot is 1,500 nm.
In this case, the temperature rises to about 1,600° C. to completely melt the silico, but the melting point is 1.412° C.ft below the melting point of the single crystallized iron.

Since the area around the beam spot where single crystallization is performed, there is a drawback that single crystallization is unstable and localized. In the post-eclipse region where this beam spot is scanned, a single crystal layer 5.6 with many grain boundaries is formed.

(4) Purpose of the Invention The present invention relates to an electron beam annealing method for crystallizing a polycrystalline layer by electron beam annealing, the purpose of which is to grow a single crystal layer over a wide area (without grain boundaries).

(5) Structure of the Invention The present invention provides a temperature variation distribution different from the conventional Gaussian type in the region on the wafer that is irradiated with the electron beam, and the melting point begins to cut off from the center of the beam, and the single crystal layer forms at this center. It seems like it will spread and form (this is a sad thing).

Therefore, in the present invention, in the electron beam annealing method, a conventional deflection means (hereinafter referred to as @1 deflection means) having a positioning function or a scanning function for electrons q, -5 is used.
A second deflection means is provided for the purpose of shaking the electron beam by applying a deflection signal having a higher frequency and periodicity than the scanning waveform of the first deflection means. Use of a beam annealing device Characteristics of the present invention (In the present invention, the temperature distribution is set so that the center of the electron beam is lower than the peripheral area, and when scanning the electron beam, Since the melting point begins to decrease from the center, the single crystal layer grows and spreads from the center of the beam.

In the conventional method, the growth of the single crystal layer narrows from the periphery of the beam, but in the case of the present invention, it grows from the center, and as a result, a wide area of the single crystal layer can be changed. become.

In this case, it is technically extremely difficult to form an electron beam with a double structure or doughnut-shaped temperature distribution with a low center using only a single spot. In the present invention, in order to solve this problem, a second deflection plate is provided and the electron beam is scanned by applying a voltage to two positions, tXX upward direction and Y direction. A beam energy state tube is formed in which the temperature at the center is substantially lower than that at the periphery by providing a first deflection plate and a second deflection plate that periodically swings the beam between two positions. This is a characteristic feature.

(6) Embodiment 2 of the invention The second WJ is an embodiment of an apparatus for realizing the electron beam annealing method according to the invention.

This equipment is composed of a main chamber 7 and a nub chamber 8. The electron beam generated at the cathode 9, which is a single gun in the WJ, is focused by the first lens lO and the second lens IIK, and placed on the wafer holder 12, so that the zero point is aligned with the optical wafer 13. The wafer holder 12 is installed on a stage 14 that is movable by a motor 13.

The present invention is characterized in that a second deflection means consisting of a deflection plate 16 is provided separately from the deflection means @1 consisting of a coil 15.

The electron beam can be swung in the direction of the deflection plate tsFix and in the Y direction, and a periodic voltage having a higher frequency than the voltage applied to the coil 16 for scanning the electron beam is applied.

Next, by the electron beam annealing method according to the present invention.

A method for converting polycrystalline silicon into a single crystal will be described. @3 As shown in Figure 3, silicon oxide 1[18t-] is grown on a silicon single crystal substrate 17, a polycrystalline silicon layer 19 is further grown, and the wafer is used as a wafer. In one type of region 20 in this wafer, the polycrystalline layer and the monocrystalline layer are in contact.

This seed region is the wafer 21 shown in FIG.
It is formed in the area 22 where the scribe is applied.

The electron beam starts from this seed region and is directed by arrow 23.
The beam spot is scanned in the direction 24 at a speed of several m/s4, but at this time, as a feature of the present invention, the beam spot is also deflected in a direction 24 perpendicular to the scanning direction.

The appropriate frequency is about 10 to 100 MHz. The diameter of the beam spot is 1100 mm.
In the case of a degree change, it is 100 to 150 mm.

Note that the arrow 25 indicates the stage 14 for moving to the 9th chip area when the beam scanning of the - chip gRbin + is completed.
It's raining on the move.

The relationship 1 between the electron beam annealing method and the Kelby pressure according to the present invention will be explained with reference to FIG. Figure 5-) shows the electron beam spot shape of a conventional device, where the temperature at the center of irradiation is high. In the figure, the high-temperature area is shown entirely with diagonal lines.

FIGS. 5(a) and 5(c) show the temperature distribution on the wafer obtained by applying a voltage to 1[16].

In this case, the waveform Fi of the voltage applied to the deflection plate 16 is shown in FIG.
It may be a sine wave as in 1) or a square wave as in (2).

Furthermore, when the voltage applied to the deflection plate 16 is shifted by the phase tπ/2 in the EX direction and the Y direction as shown in FIG. 5 (3), an annular temperature distribution as shown in FIG. 5 (13) is obtained. If the frequencies in the KX direction and the Y direction are shifted to fx=4fy as shown in FIG. 5(4), a so-called lineage waveform and a temperature distribution as shown in FIG. 5(e) can be obtained.

In this way, by operating the electron beam spot 26 so that the temperature onset and arrival □ is lower at the center than at the periphery, the polycrystalline silicon becomes single crystallized at the center as shown by the arrow 27 in FIG. Single crystallization over a wide area is achieved by growing from the center to the periphery. In this case, the temperature difference between the center and the periphery, where the temperature is highest, is set to TFi 100°C to 20G'OK.

(7) Effects of the Invention When polycrystalline silicon was single-crystallized using the electron beam annealing according to the present invention, it was different from conventional methods.

Only a single crystal region with a size of about 2 to 10 lines was obtained, and a single crystal region with a size of about -100 mm was obtained compared to the case of 9.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram illustrating the single crystallization of polycrystalline silicon by a conventional method, Fig. 2 is an electron beam annealing apparatus for carrying out the present invention, and Figs. An explanatory diagram of the case where single crystallization is performed using the method described above is shown. In the figure 10.11 Fi lens, 15 company coil, 1
6 is the deflection plate. 1st Wx -+++ ri j 1 ta) @ %4th 58th ho 6 Kinuta

Claims (1)

[Claims] In a method of manufacturing a semiconductor device in which an electron beam is irradiated onto a non-single crystal semiconductor layer provided on a substrate whose surface is made of an insulating material to achieve single crystallization, an electron gun and an electron beam tube are focused onto the wafer. an electron lens, a first deflection means for scanning or deflecting to an arbitrary location on the wafer, and applying a deflection signal having a higher frequency and periodicity than the scanning signal applied to the first deflection means; 1. A second deflection means is provided. A method for manufacturing a semiconductor device, characterized in that the electron beam is swayed at high speed by a second deflection, and the distribution of electron beam energy reaching a wafer is set.