JP2001274147A - System for producing semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate variation in the film thickness by controlling the flow rate of TRIES gas which is supplied between electrodes in a reaction chamber to a constant level, thereby controlling the gas composition at each part of a mixture gas between the electrodes at a constant level. SOLUTION: In the system for producing a semiconductor, where an SiO2 film is formed on a substrate by supplying TRIES gas and O2 gas into a reaction chamber 1 loaded with a substrate, a section 5 for making TRIES gas and O2 merge is provided immediately in front of the reaction chamber 1 and the gas merging section is provided with a turbulence generating means 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor manufacturing apparatus such as a plasma CVD apparatus used in a semiconductor manufacturing process.

[0002]

2. Description of the Related Art As one of semiconductor manufacturing processes, a plasma CVD (Chemical Vapor Deposit) for forming a predetermined film on a substrate is used.
ion) There is a film forming process. In this method, a substrate is loaded in an airtight reaction chamber, and high-frequency power is applied while supplying a reaction gas between a pair of electrodes provided in the reaction chamber to generate plasma, thereby generating gas molecules in the reaction gas. Is decomposed by plasma to cause a chemical reaction to form a thin film on the substrate surface. Usually, film formation is performed while maintaining the reaction chamber at a constant pressure.

[0003] One of such plasma CVD apparatuses is as follows.
There is a plasma CVD apparatus for forming a TRIES-SiO ₂ film. In this apparatus, TRIES [name: triethoxysilane, molecular formula HSi (OC ₂ H ₅ ) ₃ ] is used as a reaction gas.
A mixed gas of O ₂ and O ₂ is used. At room temperature, O ₂ is in the gas phase, while TRIES is in the liquid phase. For this,
After heating the liquid TRIES, the vapor TRIES
Has been used as.

FIG. 4 shows a schematic configuration of a conventional plasma CVD apparatus for forming a TRIES-SiO ₂ film. In the figure, 1 is a reaction chamber, 2 is a TRIES gas supply pipe, 3 is O
₂ gas supply pipe, 4 is a heat exchanger, 6 is a vaporizer, 7 is liquid T
RIES 8 is a mass flow controller (hereinafter referred to as “MF
C ”).

In the reaction chamber 1, a pair of upper and lower electrodes (not shown) are provided, and high-frequency power is supplied between the upper and lower electrodes while supplying a reaction gas (a mixed gas of TRIES and O ₂ ) from the upper electrode side. By generating plasma by applying the voltage, a thin film is formed on the surface of the substrate disposed on the lower electrode. An exhaust system (not shown) is connected to a lower part of the reaction chamber 1 so that the inside of the reaction chamber 1 can be maintained at a constant pressure.

In this apparatus, the liquid TRIES 7 is heated by the vaporizer 6 to become gaseous TRIES, the flow rate of which is controlled by the MFC 8, and the TRIE kept at 60 to 80 ° C.
The gas is supplied to the reaction chamber 1 through the ES gas supply pipe 2. O
_{The 2} gas supply pipe 3 is provided with a heat exchanger 4 for heating the O ₂ gas to 60 to 80 ° C., and merges with the TRIES gas supply pipe 2 at an appropriate distance before the reaction chamber. .

[0007]

However, the current TR
When a continuous film is formed by the plasma CVD apparatus for forming an IES-SiO ₂ film, there is a problem that the reproducibility of the film thickness is hardly obtained. That is, when several tens of substrates are continuously formed under the same conditions for a certain period of time in a conventional apparatus, the thickness of the TRIES-SiO ₂ film formed on the substrates varies. there were.

This variation indicates that the actual flow rate of the gas TRIES supplied between the electrodes during film formation is not constant. The cause may be that gas TRIES has condensed, gas TRIES has been converted into atomized liquid TRIES and is processed on the substrate without reacting, or a part of the mixed gas is heated inside the gas supply pipe. It is considered that it has decomposed and deteriorated.

In each case, the flow rate of TRIES supplied between the electrodes is not constant, and the gas composition (dilution ratio: O ₂ flow rate /
TRIES flow rate) is not constant.

In view of the above circumstances, the present invention controls the flow rate of the TRIES gas supplied between the electrodes in the reaction chamber to a constant value so that the gas composition (dilution ratio: O ₂ flow rate) in the portion of the mixed gas between the electrodes is reduced It is an object of the present invention to provide a semiconductor manufacturing apparatus capable of controlling a constant (/ TRIES gas flow rate) so as to eliminate variations in film thickness.

[0011]

According to the present invention, there is provided a semiconductor manufacturing apparatus for forming a SiO ₂ film on a substrate by supplying a TRIES gas and an O ₂ gas into a reaction chamber loaded with the substrate. It is characterized in that a gas merging portion for merging the TRIES gas and the O ₂ gas is provided immediately before the chamber.

In the semiconductor manufacturing apparatus according to the present invention, the TRIES gas and the O ₂ gas are merged and introduced into the reaction chamber at the gas junction provided immediately before the reaction chamber.
It is possible to prevent TRIES from condensing or becoming mist-like at and near the mixing point with _2, and as a result, it becomes possible to control the actual TRIES actual flow rate supplied between the electrodes.

According to a second aspect of the present invention, in the semiconductor manufacturing apparatus according to the first aspect, a turbulence generating means for generating a turbulent flow is provided at the gas junction.

[0014] When the gas converging section is brought close to the reaction chamber as in the first aspect of the present invention, the composition of the mixed gas is homogenized to reduce the TRI.
Naturally, it is difficult to secure a pipe length for stabilizing the ES supply amount. Therefore, according to the second aspect of the present invention, the turbulence generating means is provided at the gas merging portion so as to prevent the condensation of TRIES and to sufficiently mix the TRIES gas and the O ₂ gas. is there. Thereby, even if the distance from the mixing point to the reaction chamber is short, the gas composition in the partial portion of the mixed gas can be made uniform.

According to a third aspect of the present invention, there is provided the semiconductor manufacturing apparatus according to the first or second aspect, wherein T is set immediately before the gas junction.
A mass flow controller is provided in the RIES gas supply pipe.

As described above, TRIES immediately before the gas junction is
By providing the mass flow controller in the gas supply pipe, the actual flow rate of TRIES supplied between the electrodes in the reaction chamber can be more accurately and constantly controlled. This is because, when the mass flow controller approaches the reaction chamber, the pressure difference required for the flow control of the mass flow controller at the time of a large O ₂ flow rate can be secured, and the TRI at a predetermined pressure can be secured.
This is because the time required for the flow rates of ES and O ₂ to be stabilized (pressure adjustment time) can be improved. Also, since the mass flow controller can shorten the piping distance to the reaction chamber,
The gas remaining in the pipe can be exhausted in a short time.

According to a fourth aspect of the present invention, in the semiconductor manufacturing apparatus according to any one of the first to third aspects, the O ₂ gas is introduced at a right angle to the flow of the TRIES gas at the gas junction. It is characterized by the following.

By introducing O ₂ gas at right angles to the flow of TRIES gas at the gas junction,
At the time of merging, a necessary and sufficient mixing state can be obtained.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a semiconductor manufacturing apparatus according to the first embodiment, and the same components as those in the conventional example in FIG. 4 are denoted by the same reference numerals.

In the semiconductor manufacturing apparatus of this embodiment, the TRIES gas from the TRIES gas supply pipe 2 and the O ₂ gas supply pipe 3 are placed immediately above the upper electrode (not shown) in the reaction chamber 1.
And a gas merging section 5 for merging O ₂ gas from the air. Further, a turbulence generating means 10 for generating a turbulent flow is provided in the gas merging portion 5. The other configuration is the same as that of FIG. 4, and the description is omitted.

The TRIES gas supply pipe 2 and the O ₂ gas supply pipe 3 are both vertically connected to the turbulence generating means 10. The inside of the turbulence generating means 10 is configured so that the mixed gas passes spirally.

The liquid TRIES 7 is a vaporizer 6 (setting 60 to 60).
At 80 ° C., a TRIES vapor pressure of 30 to 90 Torr) is heated to form gaseous TRIES. ° C
Is mixed with O ₂ at the gas junction 5 immediately above the upper electrode kept warm. The O ₂ gas supply pipe 3 is provided with a heat exchanger 4 for heating O ₂ to 60 to 80 ° C.

As described above, the gas merging portion 5 immediately above the reaction chamber 1
When the TRIES gas and the O ₂ gas are mixed, TRIES does not condense or atomize at and around the mixing point, and as a result, the actual TRIES flow rate supplied between the electrodes in the reaction chamber 1 Can be controlled to be constant by the flow control system. This is because the pressure in the gas supply pipe 2 decreases as approaching the reaction chamber 1, and the lower the pressure at the mixing point, the less the condensation of TRIES gas occurs.

However, by bringing the mixing point closer to the reaction chamber 1, the composition of the mixed gas is made uniform, and it becomes naturally difficult to secure a pipe length for stabilizing the TRIES supply amount. For this purpose, a turbulence generating means 10 is provided as a solution capable of preventing condensation and sufficiently mixing. That is, by providing the means 10 for generating a turbulent flow at the mixing point of TRIES and O ₂ , the gas composition in the mixed gas portion is made uniform. The inside of the turbulence generating means 10 is configured so that the mixed gas passes in a spiral, whereby a turbulent flow of the mixed gas is generated at the mixing point, and the gas composition in the part of the mixed gas is made uniform. You.

Accordingly, since the actual flow rate of TRIES supplied between the electrodes in the reaction chamber can be controlled to be constant as described above, the variation in the film thickness can be eliminated.

Next, a description will be given of a semiconductor manufacturing apparatus according to a second embodiment, which is further improved to cope with the supply of O2 at a larger flow rate, with reference to FIG. In the semiconductor manufacturing apparatus of this embodiment, the MFC 8 is moved to a position immediately above the reaction chamber 1 and
A gas merging section 5 and turbulence generating means 10 are provided between C8 and the introduction section into the reaction chamber 1. In the gas merging section 5, O ₂ is introduced at right angles to the TRIES gas passing through the MFC 8.

By doing so, the MFC 8 can be brought closer to the reaction chamber 1 within 40 cm.
That is, the length between A and B shown in the figure can be kept within 40 cm. This can secure a pressure difference necessary for controlling the flow rate of the MFC 8 at the time of a large flow rate of O2.
Time required for the flow rates of S and O ₂ to stabilize (pressure adjustment time)
Is more improved. Also, by introducing O ₂ at right angles to the TRIES gas that has passed through the MFC 8, a necessary and sufficient mixed state can be obtained, and the mixed gas passes through an unnecessary gas supply path as in the related art. The required pressure adjustment time is not required.

Incidentally, the TRIES gas supply pipe 2 in the conventional apparatus has a long length (length between points A and B shown in the figure) from the MFC 8 to the introduction part into the reaction chamber 1 as long as 1 m or more, and furthermore at 80 ° C. Because it is heated before and after, it is easy to be clogged with impurities such as SiO ₂ generated by thermal decomposition of TRIES.
It is necessary to increase the pressure adjustment time (pressure adjustment time) until the TRIES flow rate is stabilized by increasing the length of the TRIES supply pipe 2. TRI remaining in the TRIES supply pipe 2 after film formation is required.
There were problems such as the necessity of taking a longer exhaust time for removing the ES. However, in the present embodiment, all of these problems can be solved.

FIG. 3 shows the result of comparing the time required to exhaust the inside of the reaction chamber 1 to 1.0E-3 Torr in the apparatus shown in FIGS.

In FIG. 3, the distance between AB is shown in FIGS.
2 shows the length of the pipe to the MFC 8 and the reaction chamber 1 introduction part. The evacuation time indicates the time until the inside of the reaction chamber 1 is exhausted to 1.0E-3 Torr. In the apparatus shown in FIG. 2, the use of the turbulence generating means 10 makes it possible to shorten the length of the pipe from the gas mixing section to the introduction section of the reaction chamber 1.
Was brought closer to the turbulence generating means 10, the length between A and B could be reduced to within 40 cm. On the other hand, in the apparatus of FIG. 3, the length between AB is 100 cm or more. As is clear from the graph, when the distance between A and B is shortened to within 40 cm, the evacuation time can be reduced to half or less as compared with the conventional piping.

[0031]

As described above, according to the present invention,
The actual flow rate of TRIES supplied between the electrodes in the reaction chamber can be controlled to be constant. Therefore, the gas composition in the portion of the mixed gas between the electrodes can be controlled to be constant, and the variation in the film thickness can be eliminated. Further, when the mass flow controller is provided in the TRIES gas supply pipe immediately before the gas junction, the piping distance from the mass flow controller to the reaction chamber can be shortened, so that the residual gas in the piping can be exhausted in a short time.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a semiconductor manufacturing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a semiconductor manufacturing apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing a conventional semiconductor manufacturing apparatus.

FIG. 4 is a diagram showing a relationship between a pipe length and an exhaust time.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 reaction chamber 2 TRIES gas supply pipe 3 O ₂ gas supply pipe 5 gas merging section 6 vaporizer 7 liquid TRIES 8 mass flow controller (MFC) 10 turbulence generating means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K030 AA06 AA14 BA44 EA03 FA01 KA30 KA41 5F045 AA08 AB32 AC09 AC11 AF01 BB02 DP03 EE02 EE05 EF13 5F058 BA20 BC02 BF07 BF27 BF29 BG02 BJ01 BJ02

Claims (4)

[Claims] In a semiconductor manufacturing apparatus for forming a SiO ₂ film on a substrate by supplying a TRIES gas and an O ₂ gas into a reaction chamber loaded with a substrate, a TRIE gas is formed immediately before the reaction chamber.
A semiconductor manufacturing apparatus provided with a gas merging section for merging S gas and O ₂ gas. 2. The semiconductor manufacturing apparatus according to claim 1, wherein a turbulence generating means for generating a turbulent flow is provided at the gas junction. 3. The semiconductor manufacturing apparatus according to claim 1, wherein a mass flow controller is provided in a TRIES gas supply pipe immediately before the gas junction. 4. The semiconductor manufacturing apparatus according to claim 1, wherein the gas confluence portion is configured to supply O ₂ gas to a TRIES gas flow.
A semiconductor manufacturing apparatus wherein gas is introduced at right angles.