JPH0729843A - Heat treatment system - Google Patents

Abstract

PURPOSE:To provide a technology for realizing uniform temperature distribution in an object to be treated. CONSTITUTION:In a heat treatment system wherein a semiconductor wafer 9 placed in a chamber 13, defined by a lamp house 1, a cylinder 6, and a base plate 7, is heated by a heating power supply, the heating light source comprises a group of a plurality of ring lamps having different diameters with the heating planes thereof being arranged in dome (hemispherical light source) and the setting position of the semiconductor wafer 9 is aligned with the bottom face of the hemispherical light source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for heating a sample or the like, and more particularly to a technique effective when used for heating a large-diameter semiconductor wafer.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor device, a heat treatment device is used when annealing or oxidizing a semiconductor wafer. As for this kind of device, for example, Industrial Research Council, November 1, 1983.
Published on 5th, Electronic Materials, November 1983, Supplement, 87
Page and November 20, 1985 "Electronic Materials 198
No. 5, November issue, pp. 82-88.

By the way, the present inventor examined the temperature uniformity of a semiconductor wafer in a lamp annealing apparatus using a lamp as a heating light source.

The following is a technique studied by the present inventor, and the outline thereof is as follows. That is, the lamp annealing apparatus is generally configured such that a lamp array formed by arranging straight tube type infrared lamps (for example, halogen lamps) in parallel is installed on the upper and lower surfaces of a thin box-shaped quartz process chamber. The lamps in the lamp row are arranged in parallel,
By dividing these into a plurality of zones and controlling the electric power, the temperature inside the semiconductor wafer arranged in the chamber is made uniform.

Further, in order to compensate the temperature of the edge portion where the heat of the heated semiconductor wafer is relatively dissipated, an auxiliary heating jig may be arranged in the periphery. In addition, since the demand for shallow junction formation accompanying the miniaturization of elements is a phenomenon based on a short-range atomic arrangement, the influence on lower layer elements in a three-dimensional device, the recovery of implantation damage, and the activation of impurities are
It is necessary to complete the heat treatment before the diffusion of impurities or the interfacial reaction, which poses a problem of long-distance atom transfer, do not proceed so much, and for this purpose, high temperature short time annealing is effective. The improvement of thermal efficiency in the plane of the semiconductor wafer when this high-temperature short-time annealing is performed using a lamp annealing device has conventionally been dealt with by the lamp output (electric power).

[0006]

However, as described above, the heat treatment apparatus using the parallel lamp array as the heating light source has a problem that the temperature uniformity cannot be ensured when the diameter of the semiconductor wafer is increased. Found by

That is, the temperature distribution in the semiconductor wafer surface changes depending on the illuminance distribution in the wafer surface, but even if the light irradiation intensity distribution of the lamp array is made uniform, a uniform irradiation area in the radial direction from the center of the semiconductor wafer is obtained. Since there is a limit depending on the lamp length and the illuminance distribution cannot be centered on, the tendency of illuminance decay on the outside is inevitable.

At this time, if the semiconductor wafer is rotated, the problem that the temperature distribution becomes non-uniform is solved, but the rotation mechanism is required for this, and the apparatus structure becomes complicated. Furthermore, another problem arises in keeping the atmosphere in the chamber ultra clean. In addition, the heat capacity of the heat treatment space also increases.

When the temperature in the plane of the semiconductor wafer becomes non-uniform throughout the entire annealing process, not only the device characteristics become non-uniform, but also crystal defects occur.
As the diameter of the semiconductor wafer becomes larger, the heat capacity of the semiconductor wafer and its heat treatment space must be increased, and short-time annealing becomes difficult.

Therefore, an object of the present invention is to provide a technique capable of making the temperature distribution in the object to be treated uniform by the heating source.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0012]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, a heat treatment apparatus for heating an object to be processed installed in a processing space by a heating light source, wherein the heating light source is a lamp arranged so that its heating surface has a dome shape. In addition, the arrangement position of the object to be processed is set to be the bottom surface position of the dome-shaped portion.

[0014]

According to the above-mentioned means, the heating light source provided on the inner surface of the processing space facing the processing surface of the object to be processed has a dome-shaped heat generating surface (hereinafter referred to as "hemispherical light source"). Then, the illuminance distribution on the bottom surface of the hemispherical light source becomes uniform according to the solid angle projection theorem. As a result, the temperature distribution in the object to be treated becomes uniform, and it is possible to cope with the increase in the diameter of the sample, and it is possible to improve the product yield and the throughput.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a front sectional view showing an embodiment of a heat treatment apparatus according to the present invention, and FIG. 2 is a connection diagram showing the constitution of a control system.

As shown in FIG. 1, the heat treatment apparatus has two upper and lower parts.
It can be divided, and the upper part is mainly composed of the lamp house 1, and its shape is a dome shape. Aluminum or the like is used as the material of the lamp house 1, and the light reflecting plate 2 (formed by gold plating or the like) formed on the inner surface thereof is formed. Further, on the surface of the light reflecting plate 2, a light diffusing plate 4 incorporating the ring lamp group 3 is mounted.

In the ring lamp group 3, ring lamps having different diameters (annular halogen lamps) are arranged coaxially in the light diffusing plate 4 (the ring lamp having the smallest diameter is arranged at the uppermost stage, and a predetermined number is provided). It has a structure in which the diameter is continuously increased while being spaced apart from each other). The light diffusing plate 4 is provided so that light from each lamp of the ring lamp group 3 does not have directivity, and has, for example, a structure in which numerous bubbles are formed on quartz. Furthermore, on the lower surfaces of the lamp house 1 and the light diffusion plate 4, a partition wall 5 made of a transparent member such as quartz glass is provided.

The lower part of the heat treatment apparatus is mainly composed of an annular cylinder 6 and a base plate 7 on which the cylinder 6 is mounted. Both the cylinder 6 and the base plate 7 are made of a metal such as aluminum, which is a material with a small amount of residual heat, and the inner surface is plated with gold or the like so that the light from the ring lamp can be reflected.

A plurality of support pins 8 made of quartz glass or the like are erected on the upper surface of the base plate 7, and the semiconductor wafer 9 is supported by the support pins 8. Inside the cylinder 6, at least one ring lamp 1
0 is installed. In addition, the dividing surface of the heat treatment device,
A gas introducing unit 11 and a gas discharging unit 12 are provided so that a processing gas can be introduced into and exhausted from a chamber 13 formed inside the heat treatment apparatus.

What is important here is that the central axes of the ring lamp group 3 and the ring lamp 10 coincide with the center of the semiconductor wafer 9 and the semiconductor is located at the position of the bottom surface of the spherical surface formed by the inner wall of the lamp house 1. The wafers 9 are arranged so that their surfaces are aligned with each other. By arranging in this way, a hemispherical light source is formed, and the illuminance distribution on the bottom surface of the hemispherical light source is uniform according to the solid angle projection theorem. Therefore, it becomes possible to make the temperature distribution of the semiconductor wafer 9 uniform.

In the above structure, when the semiconductor wafer is subjected to the heat treatment, only the base plate 7 is lowered while the lamp house 1 is fixed, and the semiconductor wafer 9 is set on the support pins 8 in the chamber 13 through the gap created thereby. To do. Then, the base plate 7 is lifted to make the chamber 13 airtight. The light from the ring lamp group 3 and the ring lamp 10 is transmitted to the semiconductor wafer 9
The treatment gas is introduced from the gas introduction unit 11 while irradiating the same, and the treatment is performed while the used gas is discharged from the gas discharge unit 12. At this time, the output control (power control) of the ring lamp group 3 and the ring lamp 10 is performed using the control system shown in FIG.

As shown in FIG. 2, a temperature sensor (for example, an optical pyrometer which is a kind of radiation thermometer) 14 for detecting the temperature of the central portion and the peripheral portion of the semiconductor wafer 9 is provided under the base plate 7. 15 are installed,
The measurement output is taken into the control unit 16. The control unit 16 is a PID that performs a proportional operation, an integral operation, a differential operation, etc.
It has a circuit configuration for controlling.

The control unit 16 is connected with output distribution units 17a to 17d according to the number of lamps of the ring lamp group 3 and the ring lamp 10 (here, three).
The ring lamp of the ring lamp group 3 and the ring lamp 10 are connected to each of a to 17d. Here, one ring lamp is treated as one heating zone, and it is divided into four zones A _1, A _2, A _{3, and} A ₄ , and the control unit 1
Power control (that is, heat output) is individually performed by 6.

The semiconductor wafer 9 is set in the chamber 13, and the ring lamp group 3 is driven by the controller 16 via the output distributors 17a to 17d, whereby the temperature of the semiconductor wafer 9 gradually rises. The temperature is the temperature sensor 1
4, 15 are successively measured. The control unit 16 compares the measured temperature with a preset target temperature value,
Lamp drive control is performed so that the temperature difference between the peripheral portion and the central portion of the semiconductor wafer 9 is minimized. By this control,
The temperature distribution in each part of the semiconductor wafer 9 is made uniform.

Further, in the steady heating process and the temperature lowering process, the lamp output is controlled based on the measured values of the temperature sensors 14 and 15, so that the temperature distribution of each part of the semiconductor wafer 9 is prevented from becoming nonuniform. be able to.

FIG. 3 is a characteristic diagram showing the in-plane temperature distribution of the semiconductor wafer by the heat treatment apparatus of the present invention.

In FIG. 3, the solid line characteristic shows the result of the present invention, and the dotted line characteristic shows the result of a lamp array in which tubular lamps are arranged in parallel. Regarding the dotted line characteristics, the temperature distribution is good in the uniformity of the steady heating process and the temperature decreasing process, but the temperature difference in the temperature increasing process is large, and defects or the like are likely to occur in the semiconductor wafer. On the other hand, according to the present invention of the solid line characteristic, the temperature difference between the central portion and the peripheral portion of the semiconductor wafer hardly occurs during the steady heating process as well as during the temperature raising process and the temperature lowering process. In, the temperature distribution can be made uniform.

(Embodiment 2) FIG. 4 is an enlarged sectional view of an essential portion showing the structure of the main portion of another embodiment of the present invention.

While the ring lamps are arranged above the height position of the semiconductor wafer 9 in the above-mentioned embodiment, the side lamp 18 and the base are arranged below the installation position level of the semiconductor wafer 9 in this embodiment. It is characterized in that the lamp 19 is provided so that the temperature can be made more effective.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the ring lamp can be divided into different wavelengths for zone division, whereby the optical anisotropy of the semiconductor wafer can be eliminated and heating can be performed uniformly.

Further, in the above-mentioned embodiment, the halogen lamp is used as the lamp, but the present invention is not limited to this, and a lamp that generates a necessary amount of heat may be used, or a ring-shaped lamp may be formed. It may be a heater.

Alternatively, instead of the ring lamp, a plurality of short straight pipes are arranged in a polygon (for example, a hexagon) to form one ring-shaped lamp, and the same result as the ring lamp is obtained. May be obtained.

Further, a large number of bulb-shaped lamps may be arranged in the dome-shaped light diffusing plate, and the ring lamp group 3 may be composed of innumerable point light sources. In this case, the light bulb shaped lamp is appropriately divided into a plurality of zones according to the position and controlled by the control unit 16.

Further, in the above description, the case where the invention made by the present inventor is mainly applied to the annealing process which is the application field thereof has been described, but the present invention is not limited to this and, for example, oxidation, CVD ( It is also applicable to chemical vapor deposition) and the like. Further, the present invention can be applied to multiple processes in the same chamber, such as preheating-oxidation-CVD film growth.

[0037]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1) That is, a heat treatment apparatus for heating an object to be processed installed in a processing space by a heating light source,
The heating light source is a lamp arranged so that its heat generating surface has a dome shape, and the arrangement position of the object to be processed is set to the bottom surface position of the dome portion. The temperature distribution in the processed material can be made uniform, and as a result, it is possible to cope with the increase in the diameter of the sample.

(2) Further, according to the present invention, it is possible to improve the product yield and the throughput.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of a heat treatment apparatus according to the present invention.

FIG. 2 is a connection diagram showing a configuration of a control system of the heat treatment apparatus of the present invention.

FIG. 3 is a characteristic diagram showing a temperature distribution in a semiconductor wafer by the heat treatment apparatus of the present invention.

FIG. 4 is an enlarged sectional view of an essential part showing the configuration of the main part of another embodiment of the present invention.

[Explanation of symbols]

 1 Lamp House 2 Light Reflecting Plate 3 Ring Lamp Group 4 Light Diffusing Plate 5 Partition 6 Cylinder 7 Base Plate 8 Support Pin 9 Semiconductor Wafer 10 Ring Lamp 11 Gas Introducing Part 12 Gas Exhausting Part 13 Chamber 14, 15 Temperature Sensor 16 Control Part 17a- 17d Output distribution section 18 Side lamp 19 Base lamp

Claims (5)

[Claims] 1. A heat treatment apparatus for heating an object to be processed installed in a processing space by a heating light source, wherein the heating light source is a lamp arranged so that its heat generating surface has a dome shape. Moreover, the heat treatment apparatus is characterized in that the arrangement position of the object to be processed is set to the bottom surface position of the dome-shaped portion. 2. The heat treatment apparatus according to claim 1, wherein the object to be processed is a semiconductor wafer. 3. The heat treatment apparatus according to claim 1, wherein the lamp is a ring lamp group including a plurality of ring-shaped lamps or a light bulb group including a plurality of light bulbs. 4. The ring lamp group is composed of a plurality of ring lamps having different diameters, and lamps having a larger diameter are sequentially arranged from the top of the processing space downward.
4. The heat treatment apparatus according to claim 3, wherein the lamps are arranged so as to be coaxial with the center of the object to be processed. 5. A plurality of ring lamps having different diameters are divided into a plurality of zones, and output control for these zones is performed so as to obtain a uniform temperature distribution for the object to be processed. Heat treatment equipment.