JPS63207125A - Manufacture of semiconductor element - Google Patents

Abstract

PURPOSE:To prevent the end of a silicon wafer from slipping by heat-treating with a lamp the wafer in a state that an undoped polycrystalline silicon is selectively deposited on the front or rear surface of a semiconductor substrate. CONSTITUTION:An undoped polycrystalline silicon 12 is deposited on the rear surface of a silicon wafer 11. Then, the silicon 12 is coated with a resist, patterned, and the silicon 12 is etched with the resist pattern 13 as a mark, thereby allowing the silicon 12 to remain only on a region several mm at the end of the rear surface of the wafer 11. Further, after the pattern 13 is removed, an annealing light 14 is irradiated to the wafer 11 to be heat treated with a lamp in a state that the silicon 12 remains on the end of the rear surface of the wafer 11. Thus, the temperature of the end rises due to the deposition of the silicon 12, and the temperature of the wafer 11 wholly becomes uniform. In this manner, it can prevent the end of the wafer 11 from slipping.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing semiconductor devices, and particularly to a short-time high-temperature heat treatment method (RTA: RapidT) using a lamp.
There are also notes regarding K.

(Prior Art) In the manufacturing process of semiconductor devices, high-temperature heat treatments such as annealing of ion-implanted layers and PSG flow have conventionally been performed using an electric furnace. However, recently, as a short-time heat treatment method, RTA (Rapid Thermal Treatment) using a tungsten lamp or an arc lamp has been developed.
Anneal) method has been developed and is about to be put into practical use.

A schematic cross-sectional view of the RTA device is shown in FIG. Although FIG. 5 shows a device for heating semiconductor wafers on both sides, there are other devices that have lamps on only one side.

In FIG. 5, 1 is a semiconductor wafer, 2 is a quartz tube, 3 is a tungsten-halodan lamp, 4 is a mirror, and 5 is a pyrometer.

In this device, part of the light emitted from the lamp 3 is irradiated onto the semiconductor wafer 1 through the quartz tube 2, and the other part is irradiated onto the opposite side of the wafer l, and after being reflected by the mirror 4, the light is emitted from the quartz tube 2. The semiconductor wafer l is irradiated through the beam. On semiconductor wafer l, the irradiated light is on wafer 1.
Some of it is absorbed into. The remaining light is reflected by the wafer 1 or transmitted through the wafer 1, returns to the mirror 4, and multiple reflections are repeated. As a result, the temperature of the wafer I rises in a short time, and heat treatment is performed. The increased temperature of the wafer 1 is measured by bringing a pyrometer 5 or a thermocouple (not shown) into direct contact with the semiconductor wafer 1, and the heat treatment temperature is controlled by feeding back the measured temperature to the input of the lamp 3.

(Problems to be Solved by the Invention) However, in the RTA apparatus described above, it is difficult to obtain temperature uniformity within the wafer 1 because the heat treatment is on the order of seconds. In particular, wafer 1 to be subjected to heat treatment.
As shown in Figure 6, there is almost no light incident (indicated by the solid arrow) at the end of the
(indicated by a dotted line arrow) increases, and the temperature at the end of the wafer 1 becomes lower than that at the center of the wafer 1. Further, when a quartz bottle (not shown) that supports the wafer 1 comes into contact with the end, the temperature becomes even lower due to heat conduction, and as a result, slips (crystal defects) occur at the end of the wafer 1.

In order to improve this temperature non-uniformity, mirror 4 in FIG.
A method of increasing the amount of light incident on the edge of the wafer 1 by increasing the reflectance of the area corresponding to the edge of the wafer 1,
Alternatively, there is a method in which the wafer 1 support part is shaped like a quartz ring with a heater. However, in either method, it is necessary to replace the mirror 4' or the ring-shaped heater when changing the wafer diameter. Further, as the diameter of the wafer 1 increases, this method cannot prevent slippage in the light beam.

This invention was made in view of the above points, and its purpose is to remove the entire semiconductor wafer from the entire semiconductor wafer during the lamp heat treatment process.
Another object of the present invention is to provide a method for manufacturing a semiconductor device that can prevent slip from occurring in the effective area of the wafer by limiting the occurrence of slip to only the edge of the wafer.

(Means for Solving the Problems) In the present invention, heat treatment using a lamp is carried out in a state where additive-free polycrystalline silicon is selectively deposited on the front or back surface of a semiconductor substrate.

(Function) Additive-free polycrystalline silicon is deposited, for example, on the bottom surface of a semiconductor wafer (semiconductor substrate), and this wafer is subjected to lamp heat treatment (
When performing RTA), the temperature of the wafer during RTA exhibits a different value compared to a wafer without polycrystalline silicon deposited. Figure 4 shows 3i02 formed on a silicon wafer.
Additive-free polycrystalline silicon on top of 1100n or 500n
The results show the temperature of a silicon wafer measured from the backside of the wafer using a pyrometer when RTA was performed after nm deposition.The vertical axis shows the difference in temperature from the temperature of a wafer on which polycrystalline silicon was not deposited. The horizontal axis is each setting RTA@degree. At this time, for a silicon wafer on which additive-free polycrystalline silicon is deposited, the temperature is about 20°C to 40°C (5
00 nm) The temperature is higher than that of a wafer without deposition. Therefore, by selectively depositing additive-free polycrystalline silicon as in the present invention, it becomes possible to control the temperature of the silicon wafer. Now, if additive-free polycrystalline silicon is deposited on the edge of a silicon wafer, the temperature of this edge can be raised, and as a result, the temperature of the entire wafer can be made uniform, and the temperature of the entire wafer can be increased. It is possible to prevent the occurrence of slips. -10,000 silicon wafers,
If additive-free polycrystalline silicon is deposited except for the edges, a sudden drop will occur at the edges and other parts, and as a result, the occurrence of slip will be limited to the edges, and the effective area of the wafer will be From then on, no slips were observed.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a process sectional view showing a first embodiment of the present invention. In (a) of this figure, 11 is a silicon wafer, and doped-free polycrystalline silicon 12 is deposited on the back surface of this silicon wafer 11 to a thickness of 1100 nm to 500 nm.

Thereafter, a resist is applied onto the additive-free polycrystalline silicon 12, and the additive-free polycrystalline silicon 12 is etched using the resist pattern 13 as a mask. ), it is left only in an area of a few minutes at the end of the back surface of the silicon wafer 11.

Thereafter, after removing the resist 9 turf 13, the silicon wafer 11 is exposed to an annealing light 14 as shown in FIG. , perform lamp heat treatment (RTA).

Then, in this RTA, conventionally, silicon wafer 1
In this example, the temperature at the end of the silicon wafer increases as shown in FIG. 3(a) due to the deposition of additive-free polycrystalline silicon 12. Since the temperature of the wafer 11 becomes uniform throughout, slips do not occur at the edges of the wafer 11.

FIG. 2 shows a second embodiment of the invention. In this second embodiment, after depositing additive-free polycrystalline silicon 12 to a thickness of 100 nm to 500 nm on the surface of a silicon wafer 11, the additive-free polycrystalline silicon 12 is deposited using the pattern 13a as a mask.
By etching this additive-free polycrystalline silicon 12, as shown in FIG. 2(a), a silicon wafer 1 is formed.
Silicon wafer 11 except for the proverbial area t, which is the number m of the backside edge of 1
Leave it on the back side.

After removing the resist turn 13a, 7
RTA of the silicon wafer 11 is performed by applying the Neil light 14. Then, in this second embodiment, the temperature of the region other than the edge of the silicon wafer 11 rises as shown in FIG. As a result, the occurrence of slip is limited to only the edges, and as a result, the silicon wafer 11
This prevents slippage from occurring from the effective area of the

(Effects of the Invention) As detailed above, according to the method of the present invention, by performing heat treatment using a lamp while additive-free polycrystalline silicon is selectively deposited on the front or back surface of a semiconductor substrate, Since it is possible to control the in-plane temperature profile of the semiconductor substrate during the lamp heat treatment process, it is possible to prevent the occurrence of slip that is normally formed during lamp heat treatment from the entire semiconductor substrate, or to limit the occurrence of slip to the edges of the substrate. This makes it possible to remove it from the effective area of the substrate. Further, this method can obtain good results even with large-diameter semiconductor substrates, and can easily cope with changes in the diameter of the substrate without requiring replacement of parts.

[Brief explanation of the drawing]

FIG. 1 is a process sectional view showing a first embodiment of the semiconductor device manufacturing method of Jin's invention, FIG. 2 is a process sectional view showing a second embodiment of the invention, and FIG. 1st and 2nd
Figure 4 is a characteristic diagram showing the temperature difference during RTA between a non-additive polycrystalline silicon deposited substrate and a non-deposited substrate, and Figure 5 is a temperature characteristic diagram in the radial direction of the wafer during RTA on the "A side". 6 is a diagram showing the incidence and emission of light from a semiconductor wafer during conventional RTA. 11...Silicon wafer, 12...Additive-free polycrystalline silicon, 14...7 Neil Light. /4--゛Anneal first 2vA

Claims (3)

[Claims] (1) A method for manufacturing a semiconductor device, which comprises performing heat treatment using a lamp after selectively depositing additive-free polycrystalline silicon on the front or back surface of a semiconductor substrate. (2) A method for manufacturing a semiconductor device according to claim 1, characterized in that additive-free polycrystalline silicon is deposited only in a region several millimeters from the end of the back surface of the semiconductor substrate. (3) The method for manufacturing a semiconductor device according to claim 1, wherein additive-free polycrystalline silicon is deposited except for a region several millimeters away from the end of the back surface of the semiconductor substrate.