JPH08162451A - Pressure reduced processor - Google Patents

Abstract

PURPOSE: To provide a low pressure processor capable of avoiding the reliquefaction of material gas in a chamber as well as the adverse effect on an exhaust pump due to said reliquefaction. CONSTITUTION: The low pressure processor is provided with a sample wafer holding base 3 in a chamber 2 connected to the third introduction pipe 4 of material gas comprising a liquefacted material. Within the first introduction pipe 4, a front end aperture part 4a is arranged on a holding base in the chamber 2, furthermore, a cylindrical guide for the material gas is arranged between the front end aperture part 4a of the first introduction pipe 4 and the holding base 3. This guide 7 is provided in the state of the aperture part on the holding base 3 side facing the surface of the holding base 3. Furthermore, this guide 7 is provided with heaters 9 as the heating means of the guide 7 at a specific temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a depressurization processing apparatus used when a sample surface is processed by using a source gas obtained by vaporizing a liquid substance in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art A depressurization processing apparatus used in a semiconductor device manufacturing process treats a sample surface with a raw material vaporized by vaporizing a liquid substance (hereinafter referred to as raw material gas). There is something to use. In such a device, a raw material gas obtained by previously vaporizing a liquid raw material is introduced to a gas distributor in the chamber through an introduction pipe,
The structure is such that it flows from here to the sample placed in the chamber. In order to prevent re-liquefaction of the raw material gas during introduction, for example, as described in JP-A-4-162527, The device is designed to heat the introduction tube and chamber. Here, the steam decompression device includes
Usually, a port for mounting components is provided on the outer wall of the chamber.

[0003]

However, in such a decompression treatment apparatus, it is difficult to uniformly heat the entire inside of the chamber because of the ports provided as described above and the complexity of the parts inside the container. There is a low temperature part on the inner wall of the chamber. As a result, the raw material gas emitted from the gas distributor may reliquefy and agglomerate at a low temperature before reaching the sample, which is the main cause of particle generation in the chamber. . When particles are generated in this way, maintenance must be performed frequently to keep the inside of the chamber clean.

Further, in the conventional decompression treatment apparatus, since no trap is provided in the exhaust pipe connected to the chamber, when the reliquefaction phenomenon of the raw material gas occurs in the exhaust pipe, the exhaust pump connected to the exhaust pipe is provided. There was a problem that the re-liquefied material of the source gas directly entered and the exhaust pump failed. The present invention has been made to solve the above problems, and a depressurization processing apparatus capable of preventing reliquefaction of a raw material gas in a chamber and preventing an adverse effect on the exhaust pump due to the reliquefaction of the raw material gas. It is intended to be provided.

[0005]

In the decompression treatment apparatus of the present invention, a sample holder is installed in the chamber,
The chamber is connected to an inlet pipe for a raw material gas obtained by vaporizing a liquid substance. The introduction pipe has a tip opening arranged on the holding table in the chamber, and a cylindrical guide for raw material gas is arranged between the tip opening of the introduction tube and the holding table. ing. This guide is
An opening on the side of the holding table is provided so as to face the upper surface of the holding table, and the guide is provided with heating means for heating the guide to a predetermined temperature.

An exhaust pipe is connected to the chamber,
Moreover, at least one trap and a cooler for cooling the trap may be provided in the exhaust pipe.

[0007]

In the depressurization processing apparatus of the present invention, a cylindrical guide for raw material gas is provided between the tip opening of the introduction pipe and the holding table so that the opening on the holding table side faces the upper surface of the holding table. Since the gas is provided, when the raw material gas obtained by vaporizing the liquid substance is introduced into the chamber from the introduction pipe, the raw material gas flows toward the upper surface of the holding table along the guide. At this time, since the guide is heated to a predetermined temperature by the heating means provided in the guide, the raw material gas flowing along the guide is kept at the predetermined temperature without being cooled, whereby the raw material gas is reliquefied. Without reaching, reach the surface of the sample placed on the upper surface of the holding table.

If a trap and a cooler for cooling the trap are provided in the exhaust pipe connected to the chamber, the raw material gas contained in the exhaust gas passing through the exhaust pipe is reliquefied by the trap. However, it is stored in the trap. Further, even if reliquefaction occurs before reaching the trap, the reliquefaction product is reliably removed by the trap. Therefore, the exhaust gas passing through the trap does not include the raw material gas.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the reduced pressure processing apparatus of the present invention will be described below with reference to the schematic configuration diagram shown in FIG. The present invention is an apparatus for treating a sample surface using a source gas obtained by vaporizing a liquid substance. In this embodiment, pentaethoxytantalum (Ta (OC ₂ H ₅ ) ₅ ) is used as the liquid substance and A vaporized gas (hereinafter, referred to as a vaporized gas of Ta (OC ₂ H ₅ ) ₅ ) and oxygen (O ₂ ) gas are used as source gases, and LP-CVD (Low Pressure CV) is used.
An example of a device for forming a film of tantalum oxide (Ta ₂ O ₅ ) by the method D) will be described.

Ta (OC ₂ H ₅ ) ₅ is at room temperature (5 ° C.).
It is a liquid at normal pressure (~ 35 ° C), and as shown in the vapor pressure curve of Fig. 2, the vapor pressure near room temperature (5 ° C to 35 ° C) is very low, and reliquefaction is easy near room temperature even under reduced pressure. It is easy to get up.

As shown in FIG. 1, the depressurization processing apparatus 1 is
The chamber 2 made of metal is provided, and the inside of the chamber 2 is isolated from the outside air. Further, a heater (not shown) is provided in the entire chamber 2 so that the entire chamber 2 has a predetermined temperature, that is, Ta (OC ₂ H _2
5 ) The vaporized gas of ₅ is heated under reduced pressure to a temperature at which it is difficult to reliquefy.

On the bottom side of the chamber 2 as described above,
A holding table 3 for a wafer 20 as a sample is installed.
The holding table 3 is a holding body 3 a for holding the wafer 20.
And a support 3b for supporting the same, and a heater (not shown) is built in the holder 3a.

Further, in the side wall 2a on the ceiling side of the chamber 2, vaporized gas of Ta (OC ₂ H ₅ ) ₅ and first introduction for helium (He) gas which is a carrier gas thereof are introduced at positions facing each other. The tubes 4, 4 are connected. These first
The tip ends of the introduction tubes 4 and 4 are further extended to the inside of the chamber 2, and the tip openings 4 a and 4 a thereof are arranged above the holding table 3. On the outside of the first introduction pipes 4 and 4, Ta (OC ₂ H ₅ ) ₅ that passes through the inside of the first introduction pipes 4 and 4 is provided.
A heater (not shown) is provided in order to prevent re-liquefaction of the vaporized gas.

At the first introduction pipes 4, 4, the tip opening 4 is formed.
A vaporizer (not shown) for obtaining vaporized gas of Ta (OC ₂ H ₅ ) ₅ is connected to the end portions on the opposite side to a and 4a. The vaporizer is, for example, Ta (OC ₂ H) in a liquid state.
_{5) 5} as well as bubbling with He gas as a carrier gas, and a mechanism to vaporize Ta (OC ₂ H _{5) 5} by heating the container containing Ta (OC ₂ H _{5) 5} .

A second introduction pipe 5 for oxygen gas (O ₂ ) is connected to the ceiling of the chamber 2. The tip side of the second introduction pipe 5 is extended to the inside of the chamber 2, and the tip opening 5 a thereof is the tip opening 4 of the first introduction pipes 4, 4.
a and 4a and above the holding table 3. Further, a gas disperser 6 is attached to the tip opening 5a.

In the chamber 2, and between the tip openings 4a, 4a of the first introducing pipes 4, 4 and the holding table 3, T
A cylindrical guide 7 for guiding a source gas composed of a (OC ₂ H ₅ ) ₅ vaporized gas and O ₂ gas is arranged in a state of being opened vertically. The tip openings 4a, 4a of the first introduction pipes 4, 4 are connected to the upper end opening, and the opening on the side of the holding base 3, that is, the opening on the lower end side is arranged so as to face the upper surface of the holding base 3. There is. In this example, the guide 7 has a length of 100 mm, an inner diameter on the upper end side of 100 mm, and an inner diameter on the lower end side of 130 mm, and is formed in a tapered state of expanding from the upper end side to the lower end side.

A cap 8 is attached to the upper end of the guide 7 so as to surround the gas disperser 6 and cover the upper end opening of the guide 7. The guide 7 and the cap 8 are formed of a material that does not adversely affect the processing of the surface of the wafer 20 performed in the chamber 2, such as aluminum or stainless steel.

A heater 9 as a heating means of the guide 7 is spirally wound around the outer peripheral wall of the guide 7, and the entire guide 7 is heated to a predetermined temperature by the heater 9.
That is, the vaporized gas of Ta (OC ₂ H ₅ ) ₅ is heated to a temperature at which it is not reliquefied.

On the other hand, at the bottom of the chamber 2, the exhaust pipe 1
An exhaust pump 11 made up of a broadband turbo molecular pump (TMP) is connected via 0. Two opening / closing valves 12 and 13 are attached to the exhaust pipe 10 at predetermined intervals.
A trap 14 and a cooler (not shown) arranged around the trap 14 are provided between and. The cooler is for cooling the trap 14, and is configured such that a coolant such as water or ethylene glycol circulates around the trap 14.

Next, the case where Ta ₂ O ₅ is deposited on the surface of the wafer 20 using the depressurization processing apparatus 1 configured as described above will be described. First, the holding table 3 is set to 400 ° C to 5
The chamber 2 itself is heated to 130 ° C. to 160 ° C. while being heated to the range of 00 ° C. Further, the guide 7 in the chamber 2 is heated to 140 ° C. to 180 ° C. by the heater 9, and the trap 14 is cooled to 0 ° C. to 15 ° C. by the cooler. Then, the silicon (S
A wafer 20 composed of i) and having a diameter of 5 inches is placed.

Next, the opening / closing valves 12 and 13 are opened to operate the exhaust pump 11 to exhaust the inside of the chamber 2,
The degree of vacuum in the chamber 2 is set to 1.0 × 10 ⁻⁶ Torr or more. Then, 100 to 30 O ₂ gas is introduced into the chamber 2 from the second introduction pipe 5 through the gas disperser 6 and the guide 7.
Introduce 0 SCCM. Along with this, in the vaporizer T
a (OC ₂ H ₅ ) _{5 in} a container at 110 ° C. to 14 ° C.
Ta (OC ₂ H ₅ ) ₅ is vaporized while maintaining the temperature in the range of 0 ° C., and the vaporized gas is introduced into the chamber 2 through the guide 7 from the first introduction pipe 4 together with He gas as the carrier gas. At this time, the flow rate of He gas is 80 to 200 SC.
CM and the reaction pressure in the chamber 2 is 0.1 to
Set to 1.0 Torr.

In this way, O₂gas
When the introduction of₂The gas passes through the gas disperser 6.
Therefore, it is dispersed and introduced into the guide 7 in this dispersed state.
Is done. In addition, Ta (OC₂H_Five)_FiveThe first vaporized gas
It is introduced into the guide 7 together with He gas from the introduction pipe 4,
Furthermore O₂While mixing with the gas,
That is, it flows toward the wafer 20. At this time, O₂Moth
Su, Ta (OC₂H_Five) _FiveOf vaporized gas and He gas
The flow of the mixed gas is directed toward the wafer 20 by the guide 7.
The flow is regulated. Moreover, the guide 7 is heated
The Ta (OC₂H_Five)_FiveThe vaporized gas of
It flows without cooling and reliquefaction.

Then, Ta (OC) guided by the guide 7
₂ H ₅ ) ₅ vaporized gas reacts with O ₂ gas to produce Ta ₂ O
₅ and is deposited on the surface of the wafer 20.
A Ta ₂ O ₅ film is formed on the 0 surface.

Further, Ta introduced into the chamber 2
When the vaporized gas of (OC ₂ H ₅ ) ₅ passes through the exhaust pipe 10, it is reliquefied in the cooled trap 14, and this reliquefied substance, that is, Ta (OC ₂ H ₅ ) ₅ is trapped as it is. Stored in. Therefore, the exhaust gas that has passed through the trap 14 does not include the vaporized gas of Ta (OC ₂ H ₅ ) ₅ .

Actually, when the Ta ₂ O ₅ film was repeatedly formed on the surface of the wafer 20 under the above conditions, the reliquefaction phenomenon of the vaporized gas of Ta (OC ₂ H ₅ ) _{5 on} the inner wall of the chamber 2 was observed. It was confirmed that the generation of particles in the chamber 2 was improved as compared with the conventional depressurization processing apparatus in which the guide 7 was not installed.
Further, the trap 14 stores the reliquefied gas of Ta (OC ₂ H ₅ ) ₅ vaporized gas, and the performance of the exhaust pump 11 was not deteriorated.

As described above, in the decompression processing apparatus 1 of this embodiment, the vaporized gas of Ta (OC ₂ H ₅ ) ₅ flows toward the wafer 20 without being reliquefied by the heated guide 7. , Ta (OC ₂ H ₅ ) ₅ vaporized gas is not reliquefied and aggregated, and the generation of particles in the chamber 2 is prevented, so that the frequency of maintenance of the apparatus 1 can be reduced.

Further, Ta (OC ₂ H ₅ ) is trapped in the trap 14.
₅ re liquefied material is accumulated in the vaporized gas, since the exhaust gas passing through the trap 14 does not contain the vaporized gas of _{Ta (OC 2 H 5) 5} , Ta (OC 2 H 5) 5 vaporized gas It is possible to prevent the failure of the exhaust pump 11 due to the re-liquefied substance of (2) entering the exhaust pump 11.

In the above embodiment, the present invention is applied to LP-C.
Although the case where the present invention is applied to the apparatus for performing the VD method has been described, the present invention is also applicable to the apparatus for performing the plasma CVD (PE-CVD) method, the atmospheric pressure CVD (AP-CVD) method, and the etching. Further, the size, shape, etc. of each element in the decompression processing apparatus 1 are not limited to the above examples, and can be designed as necessary within the scope not departing from the gist of the present invention.

For example, as a guide in the present invention,
It can be set in various shapes depending on the type of raw material gas used and its flow rate, and it is sufficient that the length is about 20 mm or more. Further, as an example of providing the heating means of the present invention on the guide, the case where the heater 9 is wound around the outer peripheral wall of the guide 7 has been described, but the installation method is not limited as long as the guide is heated to a predetermined temperature. Further, it goes without saying that the heating means of the present invention is not limited to the heater 9.

Further, in the decompression processing apparatus 1, the opening / closing valve 12
Although the trap 14 and the cooler are provided between the opening and closing valve 13, the trap and the cooler may not be provided in the decompression treatment apparatus of the present invention, and a plurality of traps and coolers may be provided in the exhaust pipe. Good. Further, in the steam decompression processing apparatus 1, for example, as shown in FIG. 1, a rectifier having a large number of small holes such as meshes at a height position between the bottom of the chamber 2 and the holder 3a of the holder 3. The plate 15 may be provided. When such a rectifying plate 15 is provided, the flow of the gas guided by the guide 7 toward the exhaust pipe 10 can be made uniform without being biased, so that the film formation on the surface of the wafer 20 can be made more uniform. can do.

Next, as an example in which the depressurization processing apparatus of the present invention is applied to a semiconductor device manufacturing process, a polysilicon thin film transistor (Poly-thin film transistor) provided with a gate insulating film of Ta ₂ O ₅ is used.
A case of manufacturing a SiTFT will be described with reference to the process chart of FIG.

First, as shown in FIG. 3A, a Poly-Si film is formed on a glass substrate 31 as a sample, and the Poly-Si film is formed into a predetermined pattern by lithography and etching. A predetermined impurity is doped in the portion which becomes the / drain to form the doped portion 32 and the intrinsic semiconductor portion 33 which becomes the channel of the transistor. Next, using the decompression processing apparatus 1, as shown in FIG. 3B, a gate insulating film 34 of Ta ₂ O ₅ is formed on the surface of the glass substrate 31 so as to cover the doping portion 32 and the intrinsic semiconductor portion 33.

Subsequently, as shown in FIG. 3C, a contact hole 35 reaching the doped portion 32 is formed in the gate insulating film 34 by lithography and etching, and then the gate insulating film is formed by using a sputtering device. An aluminum (Al) film is formed on 34. On this occasion,
An Al film is formed so that the contact hole 35 is also filled. Then, by lithography and etching, Al
The source electrode 36, the drain electrode 37, and the gate electrode 38 are simultaneously formed by processing the film into a predetermined pattern. Through the above steps, the Poly-Si TFT 30 having the Ta ₂ O ₅ gate insulating film 38 is manufactured.

Poly-Si T produced in this way
In the FT 30, since the gate insulating film 34 is formed by using the decompression processing apparatus 1 in which the generation of particles in the chamber 2 shown in FIG. 1 is small, the film quality of the gate insulating film 34 is very good. Therefore, by using the depressurization processing apparatus 1, Poly-S having good characteristics is obtained.
The iTFT 30 can be manufactured.

Here, the depressurization processing apparatus of the present invention is
The case where the invention is applied to the formation of the gate insulating film of the Poly-Si TFT has been described, but the application example to the semiconductor device manufacturing process of the present invention is not limited to this. For example, a gate insulating film of a field effect transistor (FET) made of single crystal Si or MI
It can also be applied to the formation of an insulating film of an M or MIS capacitor (capacitance).

[0036]

As described above, in the depressurization processing apparatus of the present invention, the raw material gas is provided between the tip opening of the introducing pipe and the holding table so that the opening on the holding table side faces the upper surface of the holding table. Since a guide for use is arranged and the guide is provided with heating means, if the guide is heated to a predetermined temperature,
The source gas introduced into the chamber can be flowed toward the upper surface of the holding table along the guide without being reliquefied by cooling. Therefore, the generation of aggregates due to the reliquefaction of the raw material gas is prevented and the generation of particles in the chamber is prevented, so that the frequency of maintenance of the apparatus can be reduced.

Further, if a trap and a cooler are provided in the exhaust pipe connected to the chamber, the raw material gas contained in the exhaust gas is reliquefied and stored in the trap, and even if it does not reach the trap again. Even if liquefaction occurs, the re-liquefied material is reliably removed by the trap, so that it is possible to prevent a failure due to the re-liquefied material of the source gas entering the exhaust pump.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a graph showing a vapor pressure curve of Ta (OC ₂ H ₅ ) ₅ .

FIG. 3 is a process drawing showing an example of a manufacturing process of a Poly-Si TFT.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Decompression treatment apparatus 2 Chamber 3 Holding stand 4 1st introduction pipe 4a Tip opening 7 Guide 9 Heater (heating means) 10 Exhaust pipe 14 Trap 20 Wafer (sample) 31 Glass substrate (sample)

Claims (2)

[Claims] 1. A decompression treatment apparatus for treating a sample surface placed in a chamber by introducing a raw material gas obtained by vaporizing a liquid substance into the chamber under a reduced pressure, wherein the sample placed in the chamber. Between the raw material gas introduction pipe connected to the chamber in a state where the tip opening is arranged on the holding table in the chamber, and the tip opening of the introduction pipe and the holding table. Placed in
And a cylindrical guide for the raw material gas, the opening of which is on the side of the holding table facing the upper surface of the holding table, and a heating means provided on the guide for heating the guide to a predetermined temperature. A reduced pressure processing apparatus comprising: 2. An exhaust pipe is connected to the chamber, and the exhaust pipe is provided with at least one trap and a cooler for cooling the trap. 1. The reduced pressure processing device according to 1.