JPS5943812B2 - 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 to deposit a layer of amorphous silicon (hereinafter referred to as α-Si) with a thickness of 4000λ in an electric furnace at 600°C, for example. Although the electric furnace method heats for about 80 minutes, it is a comparatively long heating time, so it is not practical in terms of productivity.

In addition, although increasing the temperature increases the crystal growth rate, there are disadvantages such as "warping" of silicon wafers, contamination, and therefore poor production yields. A method of short-term irradiation with a laser beam is being researched.

However, in the case of this laser beam method,
Because the α-51 layer is scanned with a small beam spot, uneven growth occurs in the boundary area between the scan lines20, and reducing the spacing between the scan lines takes time and causes excessive heating. It has been pointed out that some defects may occur. Therefore, it is said to be the newest IC circuit system.
It is said that it cannot be used in the production of "three-dimensional stacked IC circuits." 25 The purpose of the present invention is to provide a novel 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. To provide 30, the characteristics are as follows: (1) A plurality of tubular lamps are arranged with their tube axes parallel or nearly parallel to a passageway of silicon to be epitaxially grown, and the passageway is parallel or nearly parallel to the passageway of the silicon to be epitaxially grown; Place it in two planes at the sandwiching position, and turn on the tubular lamp in one plane for at least 4 seconds so that the surface of the 35 (mouth) silicon is heated to a temperature of 1100 ° C to 1,400 ° C. C) Turn on at least one of the tubular lamps in the other plane to locally raise the temperature of a part of the silicon surface to 1410'C to 1480C; (d) Then turn on the lamp in the other plane. The present invention includes a step of heating the entire area to be epitaxially grown to 141° C. to 1480° C. by switching the tubular lamps to be grown in adjacent order.

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 portion, 3 is a metal foil embedded in the seal portion, 4 and 5 are an outer conductor wire and an inner conductor wire led out from the foil, and an inner conductor wire 5.
, 5 has a length of about 16C along the tube axis! The RL filament 6 is stretched. Reference numeral 7 denotes an anchor for supporting the filament 6 on the tube shaft, and the bulb contains rare gas and a trace amount of halogen, and the bulb is known to have a 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 S-S2 and whose upper and lower sides are covered with mirrors 9. 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-S!), 10 is For example, SiO
2 and Si3N4, and 11 is an α-Sl layer, each having a thickness of about 0.5 nm. The diameter of the wafer 18 is about 10C771, with a diameter of about 0.2 μm and about 1 μm.

Here, in the insulating layer 10, as shown in an enlarged view in FIG.
The groove 12 with a width of about several μm has a width of about 50 to 500 p.m. The α-Sl layer 11 and the wafer 18 are in contact with each other via the grooves 12. 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 stacked 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 stacked IC circuit. Now, the wafer 18 is inserted into the heating furnace, and the lamp 100 in one plane S2 is
When the light is turned on, the layer of Uniha and α-Si is 3 to 5.
The temperature rises almost uniformly from 1100°C to 140°C in about seconds, so it is held at that temperature for a while, and then only the lamp 100a at the end of the wafer in the other plane S1 is turned on, and then When the adjacent right lamp (see Figure 2) is switched on and turned on, the α-S1 layer gradually changes from the left side for a predetermined period of time, and when the temperature reaches 1410°C to 1480°C, it reaches the top and the zone. For partial processing such as melting or zone refining operations, the predetermined time for which the temperature is maintained at 14100C to 1480C depends on the power consumption of the lamps, the mutual distance between the lamps, and the distance between the lamps and the wafer. Various values can be selected depending on the separation distance and switching selection speed, but the above zone is at least 0.1C! Sequentially switch and select to move at TL/sec or more.

This selection speed can actually be determined experimentally once the heating furnace is designed. In this case, the atmosphere in the furnace is preferably argon, and the s-Si that is in contact with the crystal nucleus, which is the starting point of growth, through the groove plays its role. The above epitaxial growth is preferably performed near the melting point of silicon, and if the temperature is raised to 1410°C to 1480°C for a long time over the entire area at the same time, the wafer may melt or "warp" may occur. When proceeding by a method such as lining, the epitaxial growth of the entire area of the α-Si layer is completed without damaging the wafer or causing "warpage", and there is no uneven growth. Temperature control can be relatively freely selected within the range of 1100°C to 1480°C depending on the power consumption of the lamps, the mutual distance between the lamps, the distance between the lamp and the wafer, etc. The reason for this 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.
Thermal Assist Method”. The temporary holding time may be at least 4 seconds or more.

The moving speed of the zone is 0.1 CT, with the growth temperature chosen as 1410 kinematic C-1480 near the melting point.
It is preferable to switch the lamps 100a in adjacent order so as to achieve a speed of fL/sec or more; if the speed is slower than that, excessive heating may occur or the wafer may be damaged, so it is not preferable. In addition, the molten surface bulges due to surface tension,
As it cools, defects such as unevenness on the surface appear. However, if it is too fast, there may be areas where the growth is insufficient, so it is better to set the upper limit of the movement speed to 8 wires/movement. 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 depending on whether the lamp is switched on/off, rated lighting, or over-input lighting. Therefore, 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, and there is no contamination of the wafer.
It is also extremely advantageous in preventing deformation such as "warpage".

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.
(b) A plurality of tubular lamps are arranged in two planes with their tube axes parallel or nearly parallel, parallel or almost parallel to the passage of silicon to be epitaxially grown, and at positions sandwiching the passage. ) The surface of silicon is 1
(c) Turn on at least one of the tubular lamps in the other plane for at least 4 seconds to heat the surface of the silicon to a temperature of 100'C to 1400C; Partially 1410C~1
(d) Then, the tubular lamps to be lit in the other plane are switched in the order of adjacent ones, and the entire area to be epitaxially grown is heated to 1410°C to 14°C.
By raising the temperature to 80°C, in a relatively short time,
Moreover, the entire area of α-Si on the wafer can be grown evenly.
Moreover, epitaxial growth is performed without damaging the wafer, and a growth method that is free from warping and contamination can be provided.

[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 essential parts of an example of a heating furnace for carrying out the present invention, and FIG. 3 is an explanatory diagram of a wafer. , FIG. 4 is an enlarged explanatory view of the wafer.

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 other plane is turned on so that the silicon surface is heated to a temperature between 00°C and 1400°C for at least 4 seconds; locally at 1410℃~14
The temperature was raised to 80°C, and (d) the tubular lamps to be lit in the other plane were switched in the order of adjacent ones to heat the entire area to be epitaxially grown to 1410°C to 1480°C.
A method for epitaxially growing amorphous silicon or polycrystalline silicon on a wafer, the method comprising the step of raising the temperature to ℃.