JP2000340516A - Thermal treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a thermal treatment apparatus capable of uniformly heating a wafer at a prescribed temperature throughout its surface. SOLUTION: This device is equipped with an oven chamber 34, and halogen lamps 36 which are arranged around the oven chamber 34 at nearly regular intervals so as to heat a wafer W housed in the oven chamber 34. The oven chamber 34 is equipped with a wafer tray 32 at its bottom, a gas inlet 46 located at the center of a ceiling wall 44, and a gas outlet 50 provided to a bottom wall 48. A first gas distributing plate 52 located near the gas inlet 46 and a second gas distributing plate 54 disposed near the wafer tray 32 are provided in the oven chamber 34 traversing it in parallel with the wafer tray 32. The first gas distributing plate 52 is provided with four gas spouting openings arranged on the circumference of a circle slightly smaller in diameter than the wafer. A second gas distributing plate 54 is provided with gas-spouting openings, which are arranged at regular intervals on the circumferences of concentric circles in a circular region, which is slightly larger in diameter than that of the wafer W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rapid thermal processing apparatus (RTA) for heat treatment of a wafer, and more particularly to a rapid thermal processing apparatus capable of rapidly heating a wafer to a uniform temperature in a plane. is there.

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device, a wafer is often subjected to heat treatment (annealing). For example, when ion implantation is performed on a wafer to form an impurity diffusion region such as a source / drain region, a heat treatment is performed on the wafer after the ion implantation to activate the ion-implanted impurity. The heat treatment of the wafer is usually performed by using a dedicated heat treatment apparatus, for example, a heat treatment apparatus (commonly called a lamp annealer) using an infrared lamp as a heat source.

Here, the configuration of a conventional lamp anneal will be described with reference to FIGS. 5 and 6. FIG. FIG. 5 is a schematic longitudinal sectional view showing the configuration of a conventional lamp anneal, and FIG. 6 is a plan view of the gas distribution plate viewed in the direction of arrow X in FIG. As shown in FIG. 5, a conventional lamp annealer 10 includes a furnace body 14 having a wafer loading / unloading port 12 having an openable and closable door at one end, and a rectangular furnace provided in the furnace body 14. A quartz tube 16 having a chamber therein, a wafer tray 18 arranged in a furnace chamber of the quartz tube 16, and a number of halogen lamps 20 arranged around the quartz tube 14 as a heating source are provided. The wafer W is loaded in the wafer loading / unloading port 1
2 into the furnace chamber of the quartz tube 16 and provided on the wafer tray 18 with at least three wafer supports 2
2 is placed substantially horizontally. Wafer support 22
Is provided on the upper surface of the wafer tray 18 at a distance, and supports the wafer W at a conical support point provided at the tip. Gas inlet 24 for allowing a process gas such as nitrogen gas to flow into the furnace chamber
Is provided at one end of the quartz tube 16 and a gas outlet 26 through which the process gas flows out of the furnace chamber is provided at the other end.

One or two gas distribution plates 28 stand upright on the gas inlet 24 side of the upper surface of the wafer tray 18 so as to face the gas inlet 24. Gas distribution plate 2
As shown in FIG. 6, reference numeral 8 denotes a plate-like body having a size slightly smaller than the profile of the vertical section of the quartz tube 16, and a semi-circular gas ejection port 29 through which a process gas passes is provided at the lower center. Have.

[0005] The wafer W is heated by infrared rays emitted from the halogen lamp 20. Meanwhile, a process gas such as nitrogen gas flows in from the gas inlet 22, disperses through the gas outlet 29 of the gas distribution plate 28, flows parallel to the wafer W, and then flows out of the gas outlet 26. Accordingly, it is said that the lamp annealer 10 can uniformly heat the wafer W in the wafer plane.

[0006]

In a lamp annealer for rapidly heating a wafer loaded in a quartz tube with a halogen lamp, the purpose is to heat the entire wafer to a uniform temperature. The arrangement of the lamps is important in ensuring the temperature uniformity in the wafer surface. However, even if the arrangement of the halogen lamps is devised, it is actually difficult to uniformly heat the entire wafer with the above-described conventional lamp annealer, and for example, as shown in FIG. (A portion) and a region having a high temperature (a non-hatched portion in FIG. 7) exist on the wafer, resulting in uneven temperature. FIG. 7 is an example of an in-plane temperature distribution of a wafer. When an in-plane temperature distribution is generated on the wafer, the uniformity of the heat treatment on the wafer surface is deteriorated, which causes variations in semiconductor device characteristics and a reduction in product yield.

An object of the present invention is to provide a heat treatment apparatus capable of heating a wafer to a uniform temperature in a plane.

[0008]

The present inventor has found the following as a result of studying the cause of the in-plane temperature distribution of a wafer. That is, even if the halogen lamp is arranged and heated so as to maintain the temperature uniformity in the wafer surface, a low-temperature process gas flows in from the gas inlet and flows around the wafer with an uneven flow. Therefore, the in-plane temperature distribution of the wafer changes, and the temperature uniformity is impaired. Therefore, in the lamp anneal, in addition to the arrangement of the heating lamp, it is important how the process gas flows around the wafer in a uniform distribution.

For example, the above-described conventional lamp annealer 1
In the case of 0, although one or two gas distribution plates 28 having gas ejection ports 29 are arranged,
Has only one gas outlet 29 in the lower center. As a result, when the orientation flat of the wafer W is directed toward the gas inlet 24, a process gas having a lower temperature flows into the central region than the peripheral region of the wafer W, and the temperature in the central region of the wafer W decreases. Tend to. Therefore, the in-plane temperature distribution of the wafer W becomes as shown in FIG. 7, and the in-plane heat treatment uniformity is deteriorated. Therefore, the inventor of the present invention conceived of making the in-plane temperature distribution of the wafer uniform by causing the process gas to flow uniformly around the wafer, and repeated experiments to complete the present invention. It has arrived.

In order to achieve the above object, based on the above findings, a heat treatment apparatus according to the present invention has a furnace chamber for placing a wafer on a bottom wall with the wafer surface facing upward, A plurality of lamps are provided at substantially equal intervals around the furnace chamber as a heating source for heating the wafer, and a gas inlet through which the process gas flows into the furnace chamber is provided at an upper portion of the furnace chamber, and the process gas is supplied from the furnace chamber. Gas outlets are provided on the bottom wall of the furnace chamber, respectively, and between the gas inlet and the bottom wall in the furnace chamber, a plurality of gas distribution plates penetrating the gas outlets are provided, respectively. The number and diameter of the gas outlets provided in parallel with the bottom wall of the furnace chamber and provided on the gas distribution plate, respectively,
It is characterized in that it differs for each gas distribution plate.

In the present invention, there is no limitation on the means for placing the wafer, and the wafer may be placed on a wafer tray as in the conventional case.
In the present invention, a gas inlet is provided in the upper part of the furnace chamber, and the process gas flows in a direction orthogonal to the wafer surface through a plurality of gas distribution plates having different positions, numbers, and diameters of gas outlets. This allows the process gas to flow around the wafer with a uniform distribution. In the heat treatment apparatus according to the present invention, the wafer is heated under a uniform in-plane temperature distribution of the wafer from the heating by the lamps provided at substantially equal intervals around the furnace chamber and the uniform flow of the process gas around the wafer. Can be heated.

Although the number of gas distribution plates is not limited,
In the case where the gas inlet is provided at the center of the ceiling wall of the furnace chamber, the gas distribution plate is practically the first gas close to the gas inlet.
, And a second gas distribution plate far from the gas inlet, the first gas distribution plate having four gas outlets on a concentric circle centered on the gas inlet. The second gas distribution plate has a plurality of gas ejection ports having a smaller diameter than the gas ejection ports of the first gas distribution plate dispersed in a circular region having a diameter larger than the diameter of the wafer. As a result, the process gas flowing from the gas inlet flows in a uniform distribution through the four gas outlets of the first gas distribution plate disposed on the gas inlet side, and further flows through the second gas distribution plate. Through a plurality of gas outlets having small diameters toward the wafer surface with a more uniform distribution. Therefore, it is easy to maintain the in-plane temperature distribution of the wafer.

Further, the gas outlets are provided at a plurality of positions around the wafer and are separated from each other. As a result, the direction of the exhaust gas flow of the process gas is dispersed, the flow of the process gas is not biased, and the in-plane temperature distribution of the wafer can be maintained more reliably. In a preferred embodiment of the invention, the lamps are each provided with an output adjusting device that can individually adjust the lamp output. Thereby, the wafer can be uniformly heated in the plane. As a material of the heat treatment apparatus according to the present invention, the furnace chamber, the wafer tray and the gas distribution plate are formed of quartz, and the lamp is a halogen lamp.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Embodiment Example This embodiment is an example of an embodiment of a heat treatment apparatus according to the present invention. FIG. 1 is a schematic longitudinal sectional view of the heat treatment apparatus of this embodiment, and FIG. FIG. 3 is a layout view of gas outlets of the second gas distribution plate, and FIG. 4 is a layout view of gas outlets. The heat treatment apparatus 30 according to the present embodiment is a heat treatment apparatus for a 6-inch wafer, and as shown in FIG.
, A plurality of halogen lamps 36 provided at substantially equal intervals as heating sources around the furnace chamber 34 for heating the wafers W in the furnace chamber 34, And a furnace body 38 surrounding the furnace body 34.

The wafer tray 32 is formed as a frame-shaped quartz frame, and has, on its upper surface, three wafer support portions 40 that support the wafer W with a conical portion at the tip thereof and are separated from each other. The halogen lamps 36 are configured as a large number of halogen lamp rows arranged at substantially equal intervals in order to secure the in-plane temperature uniformity of the wafer W. It can be set and adjusted. The furnace body 38 is an outer wall formed of a heat-resistant heat insulating material in order to surround the furnace chamber 34 and prevent heat from being dissipated. Prepare at the end.

The furnace chamber 34 is a chamber having a cross section of about 200 mm × about 250 mm in a quartz vessel, which accommodates the wafer tray 32 at the bottom and a gas inlet 4 at the center of the ceiling wall 44.
6 has a gas outlet 50 on the bottom wall 48 and a gate (not shown) for loading / unloading the wafer W at a location corresponding to the door 42 of the furnace body 38. The wafer W is stored in the wafer tray 32
Is placed on the wafer support part 40 and is disposed at the bottom of the furnace chamber 34 so as to be located immediately below the gas inlet 46.

In the furnace chamber 34, a first gas distribution plate 52 near the gas inlet and a second gas distribution plate 54 near the wafer tray 32 are provided between the gas inlet 46 and the wafer tray 32. A gas distribution plate is provided across the furnace chamber 34 parallel to the wafer tray 32. Thereby, the furnace chamber 3
4 is a first gas distribution chamber 56 between the gas inlet 46 and the first gas distribution plate 52, and a second gas distribution chamber 58 between the first gas distribution plate 52 and the second gas distribution plate 54. , And a wafer tray chamber 60 accommodating the wafer tray 32.

The first gas distribution plate 52 is a plate made of quartz and has a center 61 at the gas inlet 46 as shown in FIG.
Located directly under the, on the circumference of the slightly smaller circle 62 than the diameter of the diameter of the wafer W, with the arrangement where the diameter D ₁ spaced four gas ports 64 of 30mm at regular intervals. The second gas distribution plate 54 is a plate made of quartz and has a center located directly below the gas inlet 46 and a diameter slightly larger than the diameter of the wafer W (see FIG. 3), as shown in FIG. The gas outlet 66 having a diameter D ₂ of 5 mm is formed on the circumference of a plurality of concentric circles in the region
Are arranged at equal intervals. In the present embodiment,
The number of gas outlets 66 is 49. The bottom wall 48 of the furnace chamber 34
As shown in FIG. 4, 16 gas outlets 50 having a diameter D ₃ of 10 mm are provided around the wafer W at substantially equal intervals.

The process gas is supplied to the furnace chamber 3 from a gas inlet 68 through a gas inlet chamber 70 provided outside the furnace chamber 34.
4 reaches the gas inlet 46. In this embodiment, the process gas is heated by the halogen lamp 36 while flowing through the gas introduction chamber 70, so that the in-plane temperature uniformity of the wafer can be further improved. Further, the process gas reaches the gas discharge port 74 from the gas outlet 50 via the gas discharge chamber 72 provided outside the furnace chamber 34, and is discharged to the outside. In the heat treatment apparatus 30 of the present embodiment, as the process gas, oxygen, nitrogen, ammonia, nitric oxide, nitrous oxide and the like are usually used.

In this embodiment, the process gas is supplied from the gas inlet 68 to the gas inlet 46 through the gas inlet chamber 70.
From the first gas distribution chamber 56. Next, the process gas is dispersed through the gas ejection ports 62 of the first gas distribution plate 52 and flows into the second gas distribution chamber 58. At this time, the process gas is evenly distributed by the four gas ejection ports 62 having a diameter (D ₁ ) of 30 mm provided on the first gas distribution plate 52. Subsequently, the process gas is further uniformly dispersed through the gas ejection ports 66 of the second gas distribution plate 54, flows into the wafer tray chamber 60, and flows toward the wafer W. At this time, the process gas can be uniformly distributed around the wafer W because the 49 gas (D ₂ ) has a diameter (D ₂ ) of 5 mm and is uniformly dispersed by the gas ejection ports 66. Next, the gas is discharged from the gas outlet 50 to the outside through the gas discharge chamber 74 via the gas discharge chamber 72. Also in this case, the process gas has a diameter of 16 m (D ₃ ) provided on the bottom wall 48 of the furnace chamber 34 along the wafer W and concentrically.
Since the gas is uniformly exhausted through the gas outlet 50 of m, the uniform flow of the process gas around the wafer W is not disturbed.

The gas outlets 64, 66 of the first gas distribution plate 52 and the second gas distribution plate 54 shown in this embodiment.
The diameter, number, and arrangement of the gas outlets 50 provided on the bottom wall 48 of the furnace chamber 34 are examples for understanding the present invention, and the present invention is not limited to these examples. Since the optimal conditions such as the number, diameter, and arrangement of the gas ejection ports vary depending on the conditions such as the flow rate of the process gas and the dimensions of the wafer W, the number of gas ejection ports,
It is desirable to determine the aperture, arrangement, and the like by experiments and the like.

[0022]

As described above, according to the present invention, by providing a plurality of gas distribution plates having gas outlets having different diameters and numbers in the upper part of the furnace chamber, the wafer surface can be uniformly formed. Since the process gas can be introduced into the wafer, the wafer can be heat-treated at a uniform temperature in the plane. Further, by providing a plurality of gas outlets on the bottom wall of the furnace chamber along the periphery of the wafer, the process gas can be discharged in a uniform flow, so that the process gas can be dispersed more uniformly. The flow around the wafer does not cause an uneven flow of the process gas. As described above, by performing the heat treatment on the wafer using the heat treatment apparatus according to the present invention, the in-plane temperature distribution of the wafer is secured, and the product yield is improved.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a heat treatment apparatus according to an embodiment.

FIG. 2 is a layout view of gas outlets of a first gas distribution plate.

FIG. 3 is a layout view of gas outlets of a second gas distribution plate.

FIG. 4 is a layout view of a gas outlet.

FIG. 5 is a schematic longitudinal sectional view of a conventional lamp annealer.

6 is a plan view of a gas distribution plate provided in a conventional lamp annealer as viewed in the direction of arrow X in FIG.

FIG. 7 is a diagram showing an in-plane temperature distribution of a wafer.

[Explanation of symbols]

Reference numeral 10: Conventional lamp annealer, 12: Wafer loading / unloading, 14: Furnace body, 16: Quartz tube, 18: Wafer tray, 20: Halogen lamp, 22: Wafer support, 24: Gas inlet , 26 ... gas outlet, 2
8 gas distribution plate, 29 gas outlet, 30 heat treatment apparatus of embodiment, 32 wafer tray, 34
Furnace chamber, 36 Halogen lamp, 38 Furnace body, 40
.., Wafer support, 42, door, 44, ceiling wall, 46
... gas inlet, 48 ... bottom wall, 50 ... gas outlet,
52 first gas distribution plate, 54 second gas distribution plate, 5
6 first gas distribution chamber, 58 second gas distribution chamber, 60
…… Wafer tray chamber, 61 …… Center, 62 …… Circle, 64
... gas outlet, 66 ... gas outlet, 68 ... gas inlet, 70 ... gas introduction chamber, 72 ... gas discharge chamber, 74
... gas outlet.

Claims (5)

[Claims] 1. A furnace chamber for mounting a wafer on a bottom wall with a wafer surface facing upward, and a plurality of heating sources provided at substantially equal intervals around the furnace chamber as heating sources for heating the wafer in the furnace chamber. A gas inlet for flowing the process gas into the furnace chamber is provided at an upper portion of the furnace chamber, and a gas outlet for flowing the process gas from the furnace chamber is provided at a bottom wall of the furnace chamber, respectively. A plurality of gas distribution plates penetrating the gas ejection ports are provided between the gas inlet and the bottom wall of the furnace in parallel with the bottom wall of the furnace chamber, respectively. A heat treatment apparatus characterized in that the number and diameter of the jet ports are different for each gas distribution plate. 2. A gas inlet is provided at the center of the ceiling wall of the furnace chamber, and the gas distribution plate includes a first gas distribution plate near the gas inlet and a second gas distribution plate far from the gas inlet. The first gas distribution plate has four gas outlets on a concentric circle centered on the gas inlet, and the second gas distribution plate has a circular shape having a diameter larger than the diameter of the wafer. The heat treatment apparatus according to claim 1, wherein a plurality of gas ejection ports having a smaller diameter than the gas ejection ports of the first gas distribution plate are dispersed in the region. 3. The heat treatment apparatus according to claim 1, wherein the gas outlets are provided at a plurality of positions around the wafer. 4. The heat treatment apparatus according to claim 1, wherein the lamp is provided with an output adjusting device capable of individually adjusting the lamp output. 5. The furnace chamber and the gas distribution plate are formed of quartz,
The heat treatment apparatus according to any one of claims 1 to 4, wherein the lamp is a halogen lamp.