JPS5948533B2 - Method for epitaxial growth of amorphous silicon or polycrystalline silicon on a wafer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for epitaxially growing amorphous or polycrystalline silicon on a wafer.

The above method has already been introduced in several documents, but the most common method to date is
The electric furnace method heats a layer of 000 Λ amorphous silicon (hereinafter referred to as α-Si) in an electric furnace at, for example, 600° C. for about 80 minutes, but since the heating time is relatively long, it is not practical in terms of productivity.

In addition, although increasing the temperature increases the crystal growth rate, it has drawbacks such as warping and contamination of silicon wafers, resulting in poor production yields. A method of irradiating for a short period of time is being researched. However, in the case of this method using a laser beam, since the α-Si layer is scanned with a small beam spot, uneven growth occurs in the boundary area between the scanning lines, and the spacing between the scanning lines is It has been pointed out that if the size is made smaller, it will take more time and may cause excessive heating. Therefore, it is said that it cannot be used in the production of "three-dimensional stacked IC circuits," which are said to be the newest IC circuit method. An object of the present invention is to provide a new method for epitaxially growing amorphous silicon or polycrystalline silicon on a wafer, which can uniformly grow the entire area of α-Si in a relatively short time and without damaging the wafer. (a) A plurality of tubular lamps are arranged so that their tube axes are parallel or almost parallel to a path of silicon to be epitaxially grown, and the path is parallel or almost parallel to the path of silicon to be epitaxially grown. placed in two planes sandwiching 5
(1) Turn on the tubular lamps in both planes for at least 4 seconds so that the surface of the silicon is heated to a temperature of 1100°C to 1400°C; (c) Turn on the tubular lamps in the plane facing the silicon surface At least one of the lamps is turned on with excessive power to locally heat a part of the silicon surface to 1,410°C to 1,410°C.
(d) moving the silicon at a speed of at least 0.1 cm/sec or more relative to the tubular lamp in a direction perpendicular to the tube axis of the tubular lamp;
It involves a process.

The present invention will be described below with reference to Examples.

FIG. 1 is an explanatory diagram of an example of a tubular lamp used in the present invention, specifically a halogen incandescent lamp with a rated power consumption of 1 KW.

In the figure, 1 is a valve, 2 is a seal part, 3 is a metal foil embedded in the seal part, 4 and 5 are an outer conductor wire and an inner conductor wire led out from the foil, and between the inner conductor wires 5 and 5. A filament 6 with a length of about 16 cm is stretched along the tube axis. Reference numeral 7 denotes an anchor for supporting the filament 6 on the tube shaft.The bulb contains rare gas and a trace amount of halogen, and the bulb is known for its small size and long life.

FIG. 2 shows a plurality of the above-mentioned tubular lamps 100, with their tube axes parallel to each other, at positions parallel to and sandwiching the passage P of a wafer 18 having a layer of α-Si to be epitaxially grown. FIG. 2 is an explanatory view of the essential parts of an example of a heating furnace for carrying out the method of the present invention, which is arranged in two planes S1 and S2 and whose upper and lower sides are covered with mirrors 9. As shown,
The wafer 18 runs in a direction perpendicular to the tube axis of the tubular lamp 100 (in the direction of the arrow), and runs along planes S1 and S2.
．． The distance between them is 6 cIn. FIG. 3 is an explanatory diagram of an example of a wafer 18 provided with a layer of α-Si to be epitaxially grown. Specifically, wafer 1 is single crystal silicon (hereinafter referred to as s-Si), SiO2 and S
The insulating layer 11, such as i3N4, is a layer of α-Si, and its thickness is about 0.5 mm, about 0.2 μm, and about 1 μm, respectively, and the diameter of the wafer 18 is about 10 cm.

Here, as shown in an enlarged view in FIG. 4, the insulating layer 10 is provided with grooves 12 having a width of about several μm at intervals of approximately 50 to 500 μm, and the α-Si layer 11 and the wafer 18 are connected to the grooves. 12
are in contact through. Therefore, when an α-Si layer is epitaxially grown, S-Si layers are “stacked” with the insulating layer 10 in between. When manufacturing a three-dimensionally laminated 1C circuit, a through hole is appropriately provided in the insulating layer to electrically connect the upper and lower S-Si layers, thereby making it possible to manufacture a three-dimensionally laminated 1C circuit. Now, when the wafer 18 is inserted into the heating furnace and the lamps 100 in both planes are turned on, the wafer 1 and the α-Si layer are heated up in about 3 to 5 seconds.
Since the temperature rises almost uniformly from 100° C. to 1400° C., the temperature is maintained for a while, and then only the lamp 100a at the end of the wafer 1 on the other plane S1 is turned on due to excessive input power.
Wafer 1 is moved so that the entire area of wafer 1 passes directly below it. The α-Si layer is only the part directly below14
The temperature is 10° C. to 1480° C., and that portion is epitaxially grown. That is, like zone melting and zone refining operations, epitaxial growth
Lamp 1 lights up due to excessive input as wafer 1 moves.
In order to reach directly below 00a, it progresses little by little in parts, and finally it is completed over the entire area. In this case, the atmosphere in the furnace is preferably argon, and the crystal nucleus, which is the starting point of growth, is
The s-Si in contact through the groove plays this role. The above epitaxial growth is preferably carried out near the melting point of silicon, simultaneously over the entire area and for a long period of time at 1410°C to 14°C.
When the temperature rises to 80℃, the wafer may melt or warp.
However, when proceeding with a method such as zone refinement, the epitaxial growth of the entire α-Si layer can be completed without damaging the wafer or causing "warpage". There is no uneven growth.

For temperature control, the power consumption of the lamps, the mutual distance between the lamps, the distance between the lamps and the wafer, etc. can range from 1100℃ to 14℃.
It can be selected relatively freely within the range of 80°C, and the above, 1100°C
The reason for temporarily holding the temperature between 1400°C and 1400°C is that it is possible to obtain a product with less uneven growth due to uneven heating and less deformation of the wafer than by raising the temperature of the entire area directly from room temperature to the growth temperature at the same time. This is the "thermal assist method". The temporary holding time may be at least 4 seconds or more.

The moving speed of the wafer is 0.1c, since the growth temperature is selected from 1410°C to 1480°C, which is near the melting point.
It is preferable to pass directly under the over-input lamp 100a at a speed of m/sec or more; if it is slower than that, excessive heating may occur or the wafer may be damaged, so it is not preferable. Another problem is that the molten surface bulges due to surface tension, which then cools down, resulting in unevenness on the surface. however,
If the moving speed is too fast, areas with insufficient growth may occur, so it is better to set the upper limit of the moving speed to 8 cm/sec. By the way, in the method of the present invention, a tubular lamp is used as a heating source, and the total emitted light changes almost instantaneously in accordance with the switching operation of turning on/off, rated lighting, and excessive input lighting. Since it is a wafer, the temperature can be easily controlled, and since it is a lamp, it is easy to replace and maintain even if the heating source deteriorates, there is no contamination of the wafer, and it is extremely advantageous in preventing deformation such as "warping". be.

Although a halogen incandescent lamp is shown in the above embodiment, a discharge lamp such as a xenon long arc lamp may also be used with the same advantages. As can be understood from the above description, the present invention is a method for epitaxially growing amorphous silicon or polycrystalline silicon on a wafer.
(The tube axes of the tube lamps are parallel or almost parallel, and they are arranged in two planes that are parallel or almost parallel to the channel of the silicon to be epitaxially grown, and at positions sandwiching the channel. ) The surface of silicon is 11
Turn on the tubular lamps in both planes for at least 4 seconds so that they are heated to a temperature between 00°C and 1400°C (-
1) At least one of the tubular lamps in the plane facing the silicon surface is turned on with excessive power to locally raise the temperature of a part of the silicon surface to 1410°C to 1480°C, (
: Silicone is placed in a direction perpendicular to the tube axis of the tubular lamp.
By moving the lamp at a speed of at least 0.1 cm/sec relative to the tubular lamp, the entire area of α-Si on the wafer can be grown evenly and evenly on the wafer in a relatively short time. This method enables epitaxial growth without damaging the substrate, and provides a growth method that is free from warping and contamination.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an example of a tubular lamp used in the present invention, Fig. 2 is an explanatory diagram of main parts of an example of a heating furnace for carrying out the present invention, and Fig. 3 is an explanatory diagram of an example of a wafer. Figure 4 is
FIG. 1 is an enlarged explanatory view of a wafer. In the figure, 100 is a tubular lamp, 8 is a wafer, 9 is a mirror, 10 is an insulating layer, 11 is an α-Si layer, and 12 is a groove.

Claims (1)

[Claims] 1 In a method of epitaxially growing amorphous silicon or polycrystalline silicon on a wafer, (
(b) A plurality of tubular lamps are arranged in two planes with their tube axes parallel or nearly parallel, parallel or nearly parallel to the passageway of the silicon to be epitaxially grown, and at positions sandwiching the passageway; The surface of silicon is 11
(c) At least one of the tubular lamps in the plane facing the silicon surface is turned on for at least 4 seconds so that the lamps are heated to a temperature between 00°C and 1400°C; The input light is turned on to locally raise the temperature of a part of the silicon surface to 1410°C to 1480°C, and (d) the silicon is heated in a direction perpendicular to the tube axis of the tubular lamp.
A method for epitaxially growing amorphous silicon or polycrystalline silicon on a wafer, the method comprising the step of moving at a speed of at least 0.1 cm/sec or more relative to a tubular lamp.