JP2000096242A - Liquid material vaporizing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid material vaporizing device for a CVD apparatus, capable of stably and efficiently performing film formation without leaving residual products generated at vaporization on a heating metal plate for vaporizing a metallic liquid material. SOLUTION: An organic metal or an organic metal dissolved in organic solvent is prepared in a liquid material vessel 20. The temperature of a heating plate 5 disposed in the upper part of a rotor 2 in a vaporizer chamber 1 is detected by a thermocouple 7 and set at a prescribed temperature, and simultaneously, the vaporizer chamber 1 is also held at a prescribed temperature by a heat holding heater 9. Subsequently, the number of rotations of a motor 4 from empirical data is determined according to the viscosity of the liquid material, and the rotor 2 is rotated by starting the motor 4. Then, the liquid material in the prescribed quantity is dropped onto the center of the heating plate 5 via a pipe 6 by controlling the flow rate of a pump 21 or an MFC 22. The liquid material on the heating plate 5 is spread in an outside peripheral direction by the centrifugal force of the rotor 2 and vaporized by heating while enlarging liquid surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid material vaporizer and, more particularly, to a liquid material vaporizer of a CVD film forming apparatus.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, an MO
-The CVD method is actively used because it is more advantageous than the sputtering method in terms of film quality, film formation rate, and step coverage. The MO-CVD method is considered to be a thermal decomposition vapor phase growth of a group IV element, and uses an organometallic compound and a hydrogen compound which are unstable at a high temperature as raw materials for crystal growth.
In order to perform crystal growth by a vapor phase growth method, it is necessary to supply an element (or a compound containing an element) constituting a target crystal to the surface of a substrate crystal heated to an epitaxial temperature or higher by some method. . There are various methods for supplying this crystal growth raw material. Usually, a carrier hydrogen gas is bubbled into a metal organic material container whose vapor pressure is controlled at a constant temperature on a substrate heated in a hydrogen atmosphere. It is performed by flowing a hydrogen gas containing a saturated amount of an organic metal and a hydrogen compound, and forming a compound semiconductor by thermal decomposition of these raw material gases. However, recently, as a method superior to the bubbling method and the sublimation method in terms of controllability and stability, a method of vaporizing a liquid organic metal or a liquid material obtained by dissolving an organic metal in a solvent immediately before a reaction tank is used. Attention has been paid. FIG. 2 shows a conventional liquid material vaporizer. A liquid material container 20 containing a liquid material, and a pump 21 or MFC for controlling a liquid flow rate for transferring the solution.
(Mass flow controller) 22 and a pump 23 for evacuating the piping, in addition to the piping connecting the two,
A carrier gas 27 for flowing a purge gas or source gas for purging the system, a flow meter 28 for the carrier gas, a vaporizer 24 installed near the CVD reactor, a heater 25 in the vaporizer 24 and a sintered metal 26. Or, it is constituted by the heating metal plate 26. In this apparatus, a liquid material in a liquid material container 20 is supplied to a vaporizer 2 by a liquid feed pump 21 and an MFC 22.
4 and impregnates the liquid into the heated sintered metal 26 contained therein. Alternatively, the liquid is caused to pass through a gap between the heated plurality of heated metal plates 26. Alternatively, ultrasonic atomization is generated using ultrasonic waves. Except for the ultrasonic atomization method, all have structures that increase the surface area of the liquid on the heated metal to increase the efficiency of vaporization. Then, the raw material gas generated in the vaporizer 24 is sent to the CVD reaction tank together with the carrier gas 27 via the flow meter 28.

[0003]

The conventional liquid material vaporizer is constructed as described above, and the material used in this device is an organic metal or a liquid obtained by dissolving an organic metal in an organic solvent at room temperature. Many of them are thermally unstable, and it is necessary to instantaneously apply heat energy for vaporization to the liquid material. For example, next-generation DRAM
BST materials have attracted attention as high dielectric films as capacitors. Among these materials, for example, if Sr, S
A liquid obtained by dissolving an organic metal of r (dpm) 2 in an organic solvent is vaporized by a vaporizer and introduced into CVD. However, it is known that when this material is heated, evaporation and decomposition proceed simultaneously, and a residual product of a non-volatile compound is easily generated. If the non-volatile residual product remains on the sintered metal or the heated metal plate 26 of the vaporizer 24, stable vaporization is not performed even when a new metal liquid material is supplied, and the metal gas is stably introduced into the CVD. There is a problem that you can not.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid material vaporizing apparatus in which non-volatile residual products do not remain on a heated metal plate when a metal liquid material is vaporized. Aim.

[0005]

In order to achieve the above object, a liquid material vaporizer according to the present invention comprises a liquid material vaporizer for quantitatively vaporizing a plurality of or single liquid metal materials and supplying the vapor to a CVD film forming apparatus. In the above, the liquid material is dropped from a liquid material supply unit with a pipe onto a rotatable heating plate installed in a kept vaporizer, and the liquid material is spread and vaporized in the outer peripheral direction by centrifugal force of the rotating heating plate. .

The liquid material vaporizing apparatus of the present invention is configured as described above. By rotating the heating plate, the liquid material is spread outwardly by the centrifugal force and vaporized. Simultaneously, the non-volatile residual products generated during the vaporization are scattered to the outside of the rotary heating plate and scattered on the inner wall of the vaporizer, so that the new liquid material can always be stably vaporized on the rotary heating plate.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the liquid material vaporizer of the present invention will be described with reference to FIG. This device is composed of a liquid material supply unit and a vaporizer for vaporizing the liquid material,
The liquid supply unit transfers the liquid material container 20 and the liquid material.
The vaporizer comprises a pump 21 or an MFC 22 to be controlled, and the vaporizer comprises a vaporization chamber 1 (an upper lid 1a, a middle cylindrical portion 1b, and a lower base 1c), a rotating body 2 therein, and a rotation drive section for rotating the rotating body 2. It is composed of Vaporization chamber 1
The outer wall is heated to a constant temperature by a heater 9 so that vaporized molecules do not adhere to the inner wall. Also, it has a role of baking the vaporization chamber 1 to keep the inside clean. The middle cylindrical portion 1b and the lower base 1c on the inner wall side of the vaporization chamber 1 are prevented from adhering to the inner wall of the vaporization chamber 1 any scattered matter that the liquid material scatters in the circumferential direction on the rotating body 2 during vaporization. A plate 12 is provided, in particular, evaporation and decomposition proceed simultaneously at the time of vaporization of the liquid material, and a residual product of a non-volatile compound is generated. This non-volatile residual product is scattered in the circumferential direction of the rotating body 2, A shield plate 13 is provided inside the deposition-preventing plate 12 so as to prevent the scattering plate 12 from scattering upward. A heating plate 5 having good thermal conductivity is provided on the upper part of the rotating body 2, and a heater 3 is provided inside the back surface of the rotating body 2, and a current is supplied from an introduction terminal ring 8. The temperature is detected by a thermocouple 7 provided at the center rear side of the heating plate 5 to control the temperature. The rotating body 2 is rotatably sealed between the inside and the outside of the vaporization chamber 1 by a rotation introducing section 10, and its driving is performed by being connected to a motor 4 and a coupling 11. Then, a liquid material is supplied from the liquid material supply unit by a pipe 6, and the pipe 6 is arranged such that a tip end thereof is located above a center part of the rotating body 2. The liquid material dropped from the pipe 6 to the center of the heating plate 5 is vaporized by the heating plate 5, and the gas is sent from the pipe 14 to the CVD apparatus.

The operation of the apparatus will be described. First, as a material to be used, an organic metal or an organic metal is dissolved in an organic solvent, and the liquid material container 20 is prepared. The temperature of the heating plate 5 in the vaporization chamber 1 is detected by the thermocouple 7 to confirm that the temperature has reached a predetermined temperature. At the same time, it is confirmed by the controller (not shown) that the vaporization chamber 1 is at a predetermined temperature by the heat retaining heater 9 of the vaporization chamber 1. Next, the number of rotations (empirical data) is determined and rotated according to the viscosity of the liquid material. And CV
After confirming that the D device is ready, open the valves of the pipe 6 and the pipe of the pump 21 in this state, and
By controlling the flow rate by the pump 22 or 22, a predetermined amount of the liquid material is dropped onto the center of the heating plate 5 via the pipe 6. The liquid spreads in the outer peripheral direction due to the centrifugal force generated by the rotation of the rotating body 2, and is vaporized by thermal energy generated by heating the lower heater 3 while expanding the surface area of the liquid. At this time, the rotation speed is adjusted and optimized by the viscosity of the liquid so that the liquid is vaporized by the rotation until it reaches the outer periphery of the rotating body 2. This phenomenon can be observed from outside the vaporization chamber 1 through a window (not shown). Residual products generated at the time of heating remain on the upper surface of the rotating body 2 or are blown outward by centrifugal force. A heating plate 5 having good heat conductivity is attached to a liquid contact surface on the upper part of the rotator 2, and a residue blown from the rotator 2 in the vaporization chamber 1 is provided on the CVD apparatus side of the vaporization chamber 1. A shield plate 13 corresponding to a weir is provided so as not to go in the direction of the pipe 14.
Is provided. These boards are
Remove during maintenance and replace / clean. In addition, these plates are subjected to a blast treatment or the like in order to prevent the adhered products from peeling off as dust and flowing to the CVD device side. It is made of a material that serves as a catalyst for the material used. The vaporization chamber 1 is externally heated and maintained by a heat retention heater 9, and the pipe from the vaporization chamber 1 to the CVD apparatus is also kept warm, so that the vaporized gas passes through the pipe 14 without adhering to the surface. It flows to the CVD device side.

Although a magnetic fluid coupling or the like is used for the rotation introducing section 10 of the present apparatus, it is not particularly required to be a magnetic fluid coupling, and another rotating body introducing section 10 may be used. Also,
This rotating body 2 has a built-in heater 3 and thermocouple 7,
Four rows of slip rings are used for electrical transmission during rotation. As for the structure of the heater 3, the use of radiant heat from a lamp heater or the like, or electromagnetic induction heating may be used. The motor 4 may be fixed rotation if the rotation speed is optimized from the characteristics of the material used, but is preferably variable. Depending on the material to be used, the vaporization temperature is high and the temperature of the rotating body 2 is increased. However, the dropped droplets do not spread, and a heat insulating layer of vapor is formed between the droplets and the heating plate 5 to form droplets. Since the heat may not be transmitted to the rotating body 2 and the liquid body may be blown to the outer periphery in a liquid ball state, it is better to provide the rotating body 2 with a temperature gradient from the central part where the liquid drops to the outer periphery.

[0010] In the above embodiment, no carrier gas is shown other than the liquid material. However, if it is desired to use it depending on the application, it can be introduced naturally, and the gas must be blown out at a position where the product is not blown up.

[0011]

The liquid material vaporizer of the present invention is constructed as described above. In the vaporizer, the liquid material is dropped on the heated rotating body, and the surface area of the material is increased by centrifugal force. Efficiency can be improved. At the same time, non-volatile products generated at the time of heating are also dispersed in the outer peripheral direction by centrifugal force, so that the structure is difficult to flow from the vaporizer to the CVD device side, so that the stability of film formation can be obtained. Maintenance of the vaporizer is also facilitated.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a liquid material vaporizer of the present invention.

FIG. 2 is a view showing a conventional liquid material vaporizer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vaporization chamber 1a ... Upper lid 1b ... Middle cylindrical part 1c ... Lower base 2 ... Rotary body 3 ... Heater 4 ... Motor 5 ... Heating plate 6 ... Pipe 7 ... Thermocouple 8 ... Introducing terminal ring 9 ... Heating heater 10 ... Rotation introduction part 11 Coupling 12 Deposition plate 13 Shield plate 14 Pipe 20 Liquid material container 21 Pump 22 MFC 23 Pump 24 Vaporizer 25 Heater 26 Sintered metal or heated metal plate 27 ... Carrier gas or purge gas 28 ... Flow meter

Claims (1)

[Claims] 1. A liquid material vaporizer for quantitatively vaporizing a plurality of or single liquid metal materials and supplying the vaporized liquid metal material to a CVD film forming apparatus. A liquid material vaporizer characterized in that a liquid material is dropped by means of a liquid heating device, and the liquid material is spread and vaporized in the outer peripheral direction by centrifugal force of a rotary heating plate.