JP2000150499A - Low pressure cvd device and manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low pressure CVD device by which a BSG film with uniform boron concentration is formed on the surface of a semiconductor wafer without using a dispersion nozzle, and a method by which a BSG film with uniform boron concentration can be formed with good reproducibility by using a CVD device. SOLUTION: A low pressure CVD device 20 has a boat 4 holding a plurality of wafers 10 to be treated, a reaction furnace in which the boat 4 is housed, a heater 5 which is provided around the reaction furnace and heats atmosphere in the reaction furnace, and gas introducing pipes 2 and 3 through which reactive gas is introduced into the reaction furnace. In a manufacturing method which employs a CVD device 20 to form boron silicate glass(BSG) thin films on the wafers 10 to be treated, source gas containing not less than 4% wt.ratio of boron (B) is supplied through the gas introducing pipes 2 and 3 whose outlets are provided at positions lower than a position where the wafers 10 to be treated are held at 600 deg.C-800 deg.C under 1 Torr-5 Torr.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor manufacturing apparatus and a method of manufacturing a semiconductor device, and more particularly to a low-pressure CVD apparatus and a method of manufacturing a semiconductor device including a step of forming a BSG film on a semiconductor wafer using the same. .

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, an oxide film is used as a mask material in a step of selectively removing silicon by RIE (Reactive Ion Etching). Also,
When selectively stripping only the mask material after the RIE step completion, boron silicate glass doped with boron (B) in high concentration in the oxide film (B oron- S ilicate G lass, hereinafter, simply referred to as BSG) Is widely used.

[0003] Batch type LP-CVD (Low Pressure-C
A method of manufacturing a BSG film by a conventional technique using a chemical vapor deposition (apparatus) will be described with reference to FIG.

FIG. 3 is a schematic view showing a furnace structure of an example of a conventional LP-CVD apparatus. The LP-CVD apparatus 50 shown in FIG. 1 has a double-structured reaction tube having an outer tube 1 and an inner tube 6, and a boat 4 for holding a semiconductor substrate 10 which is a wafer to be processed inside the inner tube 6. Have. From the vicinity of the bottom of the inner tube 6, nozzles 3 and 52 for introducing a reaction gas are provided to extend into the inner tube 6.

[0005] The nozzle 52 is disposed up to the peripheral region of the upper end of the boat 4, and the reaction gas is introduced into the inner tube through the nozzle. The used reaction gas passes through a region sandwiched between the inner tube 6 and the outer tube 1 and has an exhaust port 12 provided at a lower portion of the apparatus.
13 to be discharged. The heating of the wafer 10 is performed by a heater 5 provided outside the reaction tube. LP-
The vacuum pump 11 is connected to the pressure reducing port 15 provided at the bottom of the CVD apparatus 50, and thereby the pressure inside the reaction tube is adjusted.

Conventionally, when a BSG film is formed using such an LP-CVD apparatus 50, boron is dispersed using a dispersion nozzle having a plurality of injection ports corresponding to the positions of the semiconductor substrates held on the boat 4. Source gas, for example,
Trimethyl borate (TMB) was introduced into the reactor.
This is to supply the source gas evenly to many semiconductor substrates, whereby a BSG film having a uniform boron concentration can be formed on the semiconductor substrates with a uniform thickness.

[0007]

However, in the film forming method using the above-mentioned dispersion nozzle, uniformity of the concentration and the film thickness largely depends on the diameter of the gas nozzle. Therefore, when the gas nozzle is replaced due to regular maintenance or the like, if the processing accuracy of the gas nozzle varies, there is a problem that reproducibility of the process cannot be obtained before and after the replacement of the nozzle.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an LP-CVD apparatus for forming a BSG film having a uniform boron concentration on the surface of a semiconductor wafer without using a dispersion nozzle, and an LP-CVD apparatus using the same. In a method of manufacturing a semiconductor device using the same, a BS having a uniform boron concentration is used.
An object of the present invention is to provide a method for forming a G film with good reproducibility.

[0009]

The present invention solves the above problems by the following means.

That is, according to the present invention, a boat for holding a plurality of wafers to be processed, a reaction furnace for accommodating the boat, and a reactor provided around the reaction furnace, which have an atmosphere in the reaction furnace of about 600 A heater for heating to a temperature of about 800 ° C. to about 800 ° C., and a source gas including a spout located below a position where the wafer to be processed is held and containing boron (B) at a concentration by weight of 4% or more. And a gas introduction pipe for introducing the gas into the reactor, and the pressure in the reactor is set to 0.1 Torr to 5 T.
decompression CVD (Ch
An emical Vapor Deposition device is provided.

It is preferable that the low pressure CVD apparatus further includes a temperature control means for controlling the heater so that the atmosphere in the reaction furnace is maintained at about 700 ° C.

[0012] More preferably, the reduced pressure CVD apparatus further includes reduced pressure control means for controlling the reduced pressure means so that the pressure in the reaction furnace is maintained at about 0.5 Torr.

Further, according to the present invention, a boat for holding a plurality of wafers to be processed, a reactor for accommodating the boat, and a heater disposed around the reactor for heating the atmosphere in the reactor. A method for manufacturing a semiconductor device, comprising: using a low-pressure CVD apparatus including a heater and a gas introduction pipe for introducing a reaction gas into the reaction furnace from an ejection port located below a position where the wafer to be processed is held. And about 600
° C to about 800 ° C and 0.1 Torr to 5 Torr
forming a thin film of boron silicate glass (BSG) on the wafer to be processed by supplying a source gas containing boron (B) at a weight ratio of 4% or more from the gas introduction pipe at a pressure of r. A method for manufacturing a semiconductor device is provided.

The above source gas preferably contains trimethyl borate (TMB) or triethyl borate (TEB).

In the above-mentioned manufacturing method, it is preferable that the atmosphere in the reaction furnace is heated to about 700 ° C.

In the above method, it is more preferable that the pressure in the reactor is about 0.5 Torr.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same portions as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a schematic diagram showing a furnace structure of one embodiment of a low pressure CVD apparatus according to the present invention. As is clear from comparison with FIG. 3, the batch type LP-
The CVD apparatus 20 is characterized in that a short nozzle 2 having an ejection port located below a position where the processing target wafer 10 is held is provided as a nozzle for guiding a source gas, instead of a dispersion nozzle. Other points are the low pressure CVD shown in FIG.
It is almost the same as the device 50.

Next, a method of manufacturing a semiconductor using the low pressure CVD apparatus 20 shown in FIG. 1 will be described as an embodiment of a method of manufacturing a semiconductor device according to the present invention. The present embodiment is characterized in that the material gas is supplied to the reaction furnace using the short nozzle 2 so that the boron concentration in the furnace becomes 4% by weight or more.

FIG. 2 shows the boron concentration in the furnace (horizontal axis: weight ratio%) and the boron concentration uniformity of the BSG film (vertical axis:%) when the BSG film is formed by the semiconductor device manufacturing method of this embodiment. FIG. 6 is a correlation diagram showing a relationship with the following. As the short nozzle 2, an L-shaped 25 mm−6 mmφ is used, and the temperature is 700
Trimethyl borate (TMB) was supplied from the short nozzle 2 as a material gas under a film forming condition of 0 ° C. and a pressure of 0.5 Torr,
In addition, ethyl orthosilicate (TEOS:
Tetraethoxysilane).

As can be seen from FIG. 2, in the region where the boron concentration in the furnace is 4% by weight or more, even when the short nozzle 2 is used, the variation in the boron concentration in the BSG film formed on the semiconductor wafer is reduced by 4%. %.

In addition, BS is formed by wet etching.
There is a process for selectively removing the G film. At this time, the selectivity with respect to the remaining oxide film depends on the boron concentration in the BSG film. Therefore, in order to obtain a sufficient selection ratio, B
It is necessary to dope the SG film with a high concentration of boron.
In this case, using the semiconductor manufacturing method of the present embodiment, the BS
If the material gas is supplied such that the boron concentration of the G film becomes 4% or more by weight, film formation using the short nozzle 2 shown in FIG. 2 is possible. Thereby, a BSG film can be formed with high reproducibility.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be variously modified and used without departing from the gist thereof. Further, materials and various film forming conditions can be changed according to required specifications. For example, in the above embodiment, trimethyl borate (TMB) was used as the boron source gas. However, the present invention is not limited to this. For example, triethyl borate (TMB) may be used.
EB) may be used. Also, the film forming conditions are not limited to 700 ° C., and good results are obtained in the range of 600 ° C. to 800 ° C. Further, regarding the pressure, 0.5 Torr
However, good uniformity can be obtained almost in the range of 0.1 Torr to 5 Torr, similarly to the uniformity shown in FIG.

[0024]

As described in detail above, the present invention has the following effects.

That is, according to the semiconductor manufacturing apparatus of the present invention, the semiconductor manufacturing apparatus has an ejection port located below a position where a wafer to be processed is held, and contains boron (B) at a weight ratio of 4% or more. Since the gas introduction pipe for introducing the source gas into the reaction furnace is provided, a BSG film having a uniform boron concentration and a uniform thickness can be formed on the surface of the wafer to be processed without using a dispersion nozzle.

Further, according to the method of manufacturing a semiconductor device of the present invention, the source gas containing boron (B) having a concentration by weight of 4% or more is injected under the position below the position where the wafer to be processed is held. Since the gas is supplied into the reaction furnace from the gas introduction tube having the outlet, a BSG film having a uniform boron concentration between wafers can be stably manufactured. Thus, even if there is some variation in the processing accuracy of the gas nozzle, it is not necessary to change the film forming conditions before and after the replacement, so that a highly reproducible semiconductor manufacturing method is provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a furnace structure of an LP-CVD apparatus used in an embodiment of a method for manufacturing a semiconductor device according to the present invention.

FIG. 2 is a correlation diagram showing a relationship between boron concentration in a furnace and boron concentration uniformity between wafers.

FIG. 3 is a schematic diagram showing a furnace structure of an example of a conventional LP-CVD apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer tube 2, 3, 52 Nozzle 4 Boat 5 Heater 6 Inner tube 8 Flange 9 Heat shielding plate 10 Wafer to be processed 11 Vacuum pump 12, 13 Discharge port 20 Low pressure CVD apparatus

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K030 AA11 BA26 BA42 BA44 EA06 FA10 GA02 JA09 JA10 KA04 KA23 KA28 KA41 LA15 5F045 AA06 AB36 AC08 AC09 AD10 AD11 AD12 AE19 AE21 AF03 BB02 BB03 BB04 DP19 DQ05 EF20 EC02 EF02 EC08 EK06 GB05 5F058 BA20 BC02 BC04 BF04 BF25 BF32 BJ02

Claims (6)

[Claims] 1. A boat for holding a plurality of wafers to be processed, a reactor for accommodating the boat, and a reactor disposed around the reactor, wherein the atmosphere in the reactor is about 600 ° C. to about 800 ° C.
A heater that heats the wafer to a temperature of about 10 ° C., and a jet port that is located below a position where the wafer to be processed is held, and the source gas containing boron (B) having a concentration by weight of 4% or more is supplied to the reaction furnace. Low pressure CVD (Chemical Vap) having a gas introduction pipe for introducing gas into the reactor, and pressure reducing means for maintaining the pressure in the reactor at 0.1 Torr to 5 Torr.
or Deposition) device. 2. The low pressure CVD according to claim 1, further comprising a temperature control means for controlling the heater so that the atmosphere in the reaction furnace is maintained at about 700 ° C.
apparatus. 3. The low-pressure CVD according to claim 1, further comprising a low-pressure control unit that controls the low-pressure unit so that the pressure in the reactor is maintained at about 0.5 Torr. apparatus. 4. A boat for holding a plurality of wafers to be processed, a reactor for accommodating the boat, a heater disposed around the reactor and heating an atmosphere in the reactor, A method for manufacturing a semiconductor device using a reduced-pressure CVD apparatus having a gas introduction pipe for introducing a reaction gas into the reaction furnace from an ejection port located below a position where a wafer is held; C. to a temperature of about 800 C. and 0.1 Torr.
At a pressure of 5 Torr, a source gas containing boron (B) at a concentration of 4% or more by weight is supplied from the gas introduction pipe to form a boron silicate glass (BS) on the wafer to be processed.
G) A method for manufacturing a semiconductor device comprising the step of forming a thin film. 5. The method according to claim 1, wherein the source gas is trimethyl borate (T
The method for manufacturing a semiconductor device according to claim 4, wherein MB: Trimethyl Borate is included. 6. The source gas is triethyl borate (T
5. The method according to claim 4, further comprising EB (Triethyl Borate).