JPH03273619A - Vertical heat treating apparatus - Google Patents

Abstract

PURPOSE:To use this apparatus in a semiconductor-wafer manufacturing process and the like, to provide thermocouples all the time even if thin pipes are provided in a reacting tube and to make it possible to control the temperature in the reacting tube accurately all the time by providing an inserting hole at the lower side part of the reacting tube, providing the thin pipes which are tightly fixed to the inner wall in the longitudinal direction, and providing temperature sensors which are inserted into the thin pipes. CONSTITUTION:A plurality of thin pipes 14 made of quartz are welded to the inner wall of a reacting tube 40. An inserting hole 15 is provided in the thin pipe 14 at a lower side 41 of the reacting tube 40. A bent part 16 is formed in the vicinity of the inserting hole 15. The inserting hole 15 is provided so as to extrude from the pipe. Many insulators 17 which are provided in the thin pipe 14 are inserted into a thermocouple 90 which is a sensor in a through hole 18 so that the insulator is freely move. The reacting tube 40 is heated with the heaters 70. For example, the temperatures of the respective parts are measured with five thermocouples 90. The powers which are applied on the heaters 70 that are divided into three zones are controlled by the measured temperatures. A control means is operated so that the inside of the reacting tube 40 becomes the constant temperature, and feedback control is performed. Impurities are diffused into a thin film. When the diffusion is finished, the supply of reaction gas is stopped. A semiconductor wafer 1 is inserted into the reacting tube 40.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a vertical heat treatment apparatus.

[Prior Art] Conventionally, CVD equipment, epitaxial equipment, thermal diffusion equipment, etc. used for forming thin films, oxide films, etc. in the semiconductor wafer manufacturing process support semiconductor wafers horizontally from the viewpoint of cross-sectional temperature uniformity. A large number of sheets, for example, 100 sheets, are stacked in parallel to each other and heated at a high temperature, for example, from 800°C to 1000°C.
A vertical straining device that can perform the treatment at °C is used. As shown in FIG. 4, the vertical heat treatment apparatus includes a reaction tube 4 in which a quartz boat 2 in which a plurality of semiconductor wafers 1, for example 100, are stacked horizontally and supported, is carried through an insertion port 3 and processed.
A reaction tube 4 is provided with a reaction gas supply port 5 connected to a reaction gas supply system (not shown), and a reaction gas exhaust port 6 connected to a reaction gas exhaust system (not shown) is provided. It is designed to be exhausted. A heater 7 divided into several regions is provided on the outer periphery of the reaction tube 4, and a heater 7 is provided at a temperature of 500°C to
It is heated to a desired temperature, such as 1200°C. A heat insulating material 8 is provided around the outer periphery of the heater 7 to prevent radiant heat from the heater 7 from escaping to the outside. Thermocouples 9 are provided through several locations of the heat insulating material 8 to measure the temperature of the outer wall of the reaction tube 4 from the outside.

In addition, Japanese Patent Publication No. 60-46787 and Japanese Utility Model Publication No. 142841/1982 disclose a method in which a thermocouple inserted into a quartz thin tube is provided inside a reaction tube.

[Problems to be Solved by the Invention] However, as described in the above publication, in the vertical heat treatment apparatus, even if a temperature sensor such as a rod-shaped thermocouple is inserted and fixed into a thin quartz tube inside the anti-core tube, the upper part of the reaction tube The temperature sensor cannot be permanently installed inside the reaction tube because it is blocked by a heating section, and a quartz boat containing wafers is carried in and taken out from the bottom of the reaction tube. Furthermore, if a temperature sensor is permanently installed, the usable area within the reaction tube becomes narrow, which is inconvenient for reloading operations since the center axis of the reaction tube and the center axis of the wafer array are different. In addition, the reaction tube must be cleaned, for example, several times a month, because residues of reactants and the like adhere to the inner wall. When cleaning the reaction tube, the reaction tube is removed from the heat treatment apparatus and immersed in a reaction solution such as hydrogen fluoride. Therefore, the thermocouple in the reaction tube must be easily attached and detached, and this cannot be achieved with vertical heat treatment equipment. Therefore, before the semiconductor is inserted into the reaction tube, a temperature sensor with a thermocouple built into a rod-shaped quartz pipe is inserted into the reaction tube, and when the sensor reaches the desired temperature, the temperature of the outer wall of the reaction tube is measured. Find the relationship between the internal and external wall temperatures. Thereafter, the sensor inserted into the reaction tube was removed, and the temperature inside the reaction tube was estimated from the temperature of the outer wall of the reaction tube, and the heating temperature of the heater was adjusted to perform processing. However, this is only an assumed value for the internal temperature, and the temperature inside the reaction tube could not be actually measured, making highly accurate temperature control impossible.

The present invention was made in order to eliminate the above-mentioned drawbacks, and even in a vertical furnace, a sensor is installed inside the reaction tube, and the temperature inside the reaction tube can be controlled uniformly with high precision. The purpose is to provide a heat treatment device.

[Means for Solving the Problems] In order to achieve the above object, the vertical heat treatment apparatus of the present invention has the following features:
In a vertical heat treatment apparatus in which a plurality of objects to be treated are placed in a boat and the boat is housed in a reaction tube for treatment, an insertion port is provided at the lower side of the reaction tube, and the boat is installed on the inner wall in the longitudinal direction of the reaction tube. This device includes a fixed thin tube and a bendable temperature sensor inserted into the thin tube.

[Function] A thin tube is attached and fixed to the inner wall of the reaction tube of a vertical heat treatment apparatus in which a storage boat in which a large number of objects to be processed are stacked is arranged in a reaction tube so as not to come into contact with the objects to be processed and the support for the objects to be processed. let The mouth of this thin tube is bent so that an insertion port protrudes from the lower side of the reaction tube. A bendable sensor is inserted through this insertion opening. Therefore, even in a vertical heat treatment apparatus, since a temperature sensor is permanently installed inside the reaction tube while the reaction is being performed, the temperature inside the reaction tube can be accurately feedback-controlled to perform heat treatment.

[Example] An example in which the vertical heat treatment apparatus of the present invention is applied to a diffusion apparatus in a semiconductor wafer manufacturing process will be described with reference to the drawings.

In the vertical heat treatment apparatus shown in FIG. 1, a diffusion bag [K is a quartz boat 2 with a longitudinal length of about 600 mm, in which a plurality of semiconductor wafers, for example, 100 semiconductor wafers L, which are stacked horizontally and supported, are carried in through the insertion port 30. A reaction tube 40 is provided in which the process is carried out. The reaction tube 40 has a length of about 1100 mm in the longitudinal direction, and is provided with a reaction gas supply port 50 connected to a reaction gas supply system (not shown), and connected to a reaction gas exhaust system (not shown). The reaction gas is discharged from the exhaust port 60. A heater 70 is provided surrounding the reaction tube 40 and divided into several regions, each of which performs heat treatment. A cooling gas inlet 10 is provided on the outer periphery of the heater 70.
A heat insulating material 80 is provided with a passage for cooling gas supplied from the cooling gas outlet 11, and the cooling gas is sucked by a vacuum device or the like and exhausted from the cooling gas outlet 11. Further, in the reaction tube 40, there is provided a mounting metal fitting 3 on which a rotatable quartz boat 2 is placed, connected to the motor 12, in order to uniformly process the wafer, which is the object to be processed.

Furthermore, a thin tube 14 made of quartz is welded to the inner wall of the reaction tube 40. The thin tube 14 is thin so as not to contact the semiconductor wafer 1 or the quartz boat 2, and has an outer diameter of 5 mmφ and an inner diameter of 3 mm, for example, and has an insertion port 15 on the lower side 41 of the reaction tube 40.
It is provided with a curved part 6 near 5 so that the insertion port 15 protrudes.

As shown in FIG. 2, a plurality of thin tubes 14 are provided so that their tips are located at desired temperature measurement positions of the reaction tube 40. Inside this thin tube 14, as shown in FIG. 3, a large number of cylindrical insulators 17 made of, for example, alumina ceramic are provided in a bead shape. The insulator 17 has a diameter of 2.5 mm and a length of 5, for example.
Two through holes 18 with a diameter of 0.7 mm and a diameter of 0.7 mm are provided, and a platinum wire 91 and a rhodium wire 92 having a diameter of Q and a diameter of 5 mm, for example, forming a thermocouple 9o serving as a sensor are loosely passed through the through holes 18. . Terminals of the platinum wire 91 and the rhodium wire 92 are each led out from the insertion port 15 of the thin tube 14 and connected to the power supply device. Since the insulators 17 act as a cushioning material and are provided in large numbers in the form of a bead, the platinum wires 91 and the rhodium wires 92 are allowed to pass loosely through the curved portions 16 without coming into contact with each other.
It can also be inserted into and taken out from the insertion port 15 into a quartz microtube 14 having a diameter.

The operation of the diffusion device configured as above will be explained.

The semiconductor wafer 1 supported by the quartz boat 2 is inserted into the insertion port 30
It is inserted into the reaction tube 40 from the inside. The insertion port 30 is closed by a lid, and a predetermined amount of a reaction gas such as a hydride or a halide is supplied into the reaction tube 40 from the reaction gas supply port 50 and exhausted from the reaction gas exhaust port 60. The reaction tube 40 is heated to a desired temperature by the heater 70. Then, during the reaction process, the temperature of each part is measured using at least three or, for example, five thermocouples 90. Based on the measured temperature, the electric power applied to the heater 70 divided into, for example, three zones is controlled, and a control means (not shown) is operated to perform feedback control so that the inside of the reaction tube 40 reaches a desired constant temperature. In this way, impurities are diffused into the thin film, and when the reaction is completed, the supply of the reaction gas is stopped, and the cooling gas supplied from the cooling gas inlet 10 is sucked in, for example, air from the cooling gas outlet 11 to the surroundings of the heater 70. The reaction tube 40 is cooled by circulating the cooling gas.

The above description is an explanation of one embodiment of the present invention, and the present invention is not limited thereto, and can be applied not only to a diffusion device but also to any heat treatment device such as a CVD device or a plasma device. . Moreover, it can be applied not only to a vertical furnace but also to a horizontal furnace.

[Effects of the Invention] As is clear from the above explanation, according to the vertical heat treatment apparatus of the present invention, a thermocouple can be permanently installed even if a thin tube with an insertion port is provided at the lower side of the reaction tube. , the temperature inside the reaction tube can be precisely controlled at all times.

[Brief explanation of drawings]

Fig. 1 shows the structure and components of an embodiment of the vertical heat treatment apparatus of the present invention, Figs. 2 and 3 show main parts of the embodiment shown in Fig. 1, and Fig. 4 shows a conventional example. FIG. l... Semiconductor wafer (object to be processed) 40...
...Reaction tube 41 ... Lower part 14 ... Thin tube 15 ... Insertion port 16 ... Bend section 90 ... Sensor (thermocouple) K ... ...Diffusion device (vertical heat treatment device) Figure 1/゛

Claims (1)

[Claims] In a vertical heat treatment apparatus in which a plurality of objects to be treated are provided in a boat and the boat is accommodated in a reaction tube from below for treatment, an insertion port is provided at the lower side of the reaction tube, and an inner wall in the longitudinal direction of the reaction tube is provided. 1. A vertical heat treatment apparatus comprising: a thin tube closely fixed to the thin tube; and a bendable temperature sensor inserted into the thin tube.