JP2667364B2 - Film forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus, and more particularly to a film forming apparatus for activating a reactive gas to form an insulating film or the like by a CVD method (chemical vapor deposition).

[0002]

_2. Description of the Related Art A CVD apparatus is used in the manufacture of semiconductor devices such as SiO ₂ film, PSG film, BSG film, BPSG film, Si ₃ N ₄ film, amorphous Si film, polycrystalline Si film, W film and Mo film. , WSi ₂ film, MoSi ₂ film,
This is a film forming apparatus useful for forming an Al film or the like. When the conventional CVD apparatuses are classified by means of activating the reaction gas, the main ones are a thermal CVD apparatus, an optical CVD apparatus, and a plasma CVD apparatus.

[0003] Among the above, the thermal CVD apparatus has a heating means for activating the reaction gas by heating the reaction gas to give thermal energy to the reaction gas, and is classified into a low pressure and a normal pressure according to the pressure used. Is done. In addition, it is classified into low temperature and high temperature according to the substrate temperature.
It is classified into induction heating and lamp heating. Further, it is classified into a hot wall type and a cold wall type depending on the installation location of the heating means.

Further, the photo-CVD apparatus uses a light irradiating means for irradiating the reaction gas with ultraviolet rays to give light energy to the reaction gas to activate the reaction gas, and the film is formed under a low pressure or a high pressure and at a low temperature. Formation is possible. Further, the plasma CVD apparatus uses plasma generating means for directly or indirectly activating the reaction gas using AC power or a magnetic field, and is generally performed at a low pressure and a low temperature. The plasma generating means is classified into a parallel plate type that directly activates the reaction gas by radiating high frequency power, and an ECR type that gives energy to electrons by high frequency power and magnetic field and indirectly activates the reaction gas by the electrons. Is done.

[0005]

However, the above-described film forming method using a thermal CVD apparatus is not preferable in some cases because the temperature of the substrate becomes high. Further, there is room for improvement in terms of film quality such as denseness. Further, in the film forming method using an optical CVD apparatus, a film is formed in an unnecessary place, which causes generation of particles and the like. Furthermore, the deposition rate is slow and there is room for improvement in practical use.

Further, a film forming method using a plasma CVD apparatus, particularly a parallel plate type, causes substrate damage due to plasma irradiation. For this reason, the ECR type plasma CVD method is used especially when the substrate damage is a problem. In this case, it is effective in preventing damage to the substrate and forming a dense film, but the frequency is 2.45 GHz.
The use of such an ultra-high frequency requires a large-scale device.

In particular, in the plasma CVD apparatus, in order to improve the plasma generation efficiency or suppress the variation in the film thickness to improve the uniformity, the shape of the introducing pipe for the film-forming gas or the like and the inside of the chamber are set. The location of the gas outlet is important. The present invention has been created in view of the problems of the related art, a simple device configuration, it is possible to form an insulating film of good film quality, further improve the plasma generation efficiency, or the formation film It is an object of the present invention to provide a film forming apparatus capable of suppressing variation in film thickness and improving uniformity.

[0008]

The above object is the first invention, that is, the first gas introducing pipe guides the first reaction gas to the plasma generating portion to generate plasma, and the second gas introducing pipe. In the film forming apparatus for guiding the second reaction gas to the film forming section by the above, and activating the second reaction gas by the plasma to form a film on the substrate, the first gas introducing pipe is A gas conduit provided with a plurality of gas discharge holes, and a first reaction gas discharged from the gas discharge holes received on a plate surface;
And a relay plate attached to an end of the gas conduit, which is guided from the plate surface to an edge of the plate surface and then flows to the film forming unit downstream. ,
According to a second aspect of the present invention, the second gas introduction pipe has a ring shape, includes a plurality of gas discharge holes along a pipe wall of the ring, and is positioned below the relay plate in parallel with the relay plate. The problem is solved by the film forming apparatus according to the first aspect of the present invention.

[0009]

[Operation] In the film forming apparatus according to the present invention, the first gas introduction tool communicates with a chamber forming the plasma generation chamber in the upstream central portion of the plasma generation chamber, or is arranged in the central portion of the plasma generation chamber. Therefore, an electromagnetic field for generating plasma is effectively applied to the first reaction gas. Therefore, the plasma generation efficiency is good.

Further, since the moving distance of the reaction gas is lengthened by receiving the released first reaction gas by the relay plate and moving it on the relay plate, it is possible to promote the formation of plasma. This improves the plasma generation efficiency.
Further, since the gas releasing portion of the gas introducing tool is arranged on the substrate, the reaction gas is uniformly supplied on the substrate. Therefore, the uniformity of the film thickness is improved.

Further, since the gas releasing portion is formed in a ring shape, plasma flowing from the upstream of the film forming portion, for example, plasma narrowed to the central region of the film forming portion by a magnetic field easily passes through. As the first gas introducing tool and the CVD apparatus equipped with the gas introducing tool, a frequency of 13.56 MHz is set in the plasma generating unit.
CV having an external antenna for radiating high-frequency electric power and a source solenoid for forming a magnetic field in the plasma generation unit
A D apparatus is used. Therefore, helicon mode high-density plasma can be generated in the plasma generation unit, and a highly dense film is formed.

Further, since the frequency of the high frequency power applied to the external antenna is 13.56 MHz, the equipment such as a waveguide for generating the high frequency power of 2.45 GHz which is extremely high as in the case of the ECR type is unnecessary. The device configuration is simple. Further, a gas introduction tool is provided above the substrate separately from the first gas introduction tool. Therefore, the reaction gases can be prevented from reacting with each other during the supply of the reaction gas onto the substrate, and the generation of particles can be prevented.

[0013]

Next, an embodiment of the present invention will be described with reference to the drawings. (1) Description of CVD film forming apparatus using helicon mode plasma according to the first embodiment of the present invention FIG. 1 is a side view showing the overall configuration of the CVD apparatus according to the first embodiment of the present invention. FIG. In this embodiment, a CVD apparatus using helicon mode plasma will be exemplified.

In FIG. 1, 1 is 15 cm in diameter × 2 in length.
A first reaction gas introduced from a first reaction gas introduction pipe (first gas introduction tool) 8 in a plasma generation chamber (plasma generation unit) partitioned from the outside by a chamber 1a made of 5 cm cylindrical quartz. A gas, for example, an oxygen gas (O ₂ gas) is activated. The shape of the first reaction gas introduction pipe 8 and the arrangement of the gas discharge ports of the first reaction gas introduction pipe 8 in the plasma generation chamber 1 can be variously considered. Reference numeral 8 denotes an elongated quartz tube having an outer diameter of 6.35 mm and an inner diameter of 4 mm, and communicates with the upstream central portion of a chamber forming the plasma generation chamber 1.

Reference numeral 2 denotes an external antenna mounted around the plasma generation chamber 1. Two ring-shaped conductors orbit the upper and lower peripheral portions of the cylindrical plasma generation chamber 1 at a predetermined interval. The distance between the two annular conductors is important for adjusting the wave number of the helicon wave, that is, the plasma density. FIG. 2 shows an example of the shape of the external antenna 2.
In this case, RF is applied to the two annular conductors in opposite directions.
A current flows, and a helicon wave of zero mode is formed. By changing the shape of the external antenna, a higher-order mode helicon wave can be formed.

Reference numeral 3 denotes a matching network connected to the external antenna 2, and reference numeral 4 denotes an RF power supply for supplying RF power having a frequency of 13.56 MHz to the external antenna 2 via the matching network 3. RF power is the energy source for plasma generation. 5 is a cylindrical inner source solenoid provided around the plasma generation chamber 1, 6 is a cylindrical outer source solenoid provided around the inner source solenoid 5, and the inner source solenoid 5 and the outer source solenoid 6 are: A magnetic field is formed in the plasma generation chamber 1 in the axial direction.
Such a magnetic field is required to form a helicon wave and adjust the plasma density. FIG. 3 shows the relationship between the current flowing through the inner solenoid 5 and the outer solenoid 6 and the generated magnetic field. I _IO indicates the current of the inner solenoid 5, and I _OS indicates the current of the outer solenoid 6.

The above is the high density (10 ¹² cm ^-3 ) of the helicon mode.
Plasma generation chamber 1 necessary for plasma generation described above
And the peripheral device configuration, especially RF power,
The magnetic field and the distance between the two annular conductors of the external antenna 2 are important parameters for plasma generation. Reference numeral 7 denotes a film forming chamber (film forming portion) which is connected to the plasma generating chamber 1 downstream of the plasma generating chamber 1 and is partitioned from the outside by a cylindrical chamber 7a having an inner diameter of 30 cm and a length of 22.5 cm.

The film forming chamber 7 is provided with a second reaction gas introduction pipe (gas introduction tool) 9 having a gas discharge section 9a for introducing and discharging a second reaction gas. The helicon mode plasma composed of the first reaction gas generated in the plasma generation chamber 1 is supplied to the film formation chamber 7 and the second
A second reaction gas, for example, TE
OS gas is introduced into the film formation chamber 7. The helicon mode plasma moves downstream and activates the TEOS gas. As a result, the activated TEOS gas reacts with oxygen plasma to deposit a silicon oxide film on the wafer 20.

The shape of the gas releasing portion 9a of the second reaction gas introducing pipe 9 and the arrangement of the gas releasing portion 9a in the film forming chamber 7 can be variously considered, but in the case of the embodiment, FIG. , (B)
As shown in the figure, an elongated quartz tube (first gas conduit) 21a for guiding the second reaction gas to the film forming chamber 7, an outer diameter 6.35 mm, and an inner diameter branched into two and communicating with the quartz tube 21a. 4mm long quartz tubes (second gas conduits) 22a and 22b with a diameter of about 2
And a 3 cm ring-shaped gas releasing portion 9a. In this case, the second group of gas conduits 22a and 22b branched into two from the first gas conduit 21a orbit 180 degrees in opposite directions to each other and unite again at the pipe end to form a ring. And the second
The inner passages of the gas conduits 22a and 22b communicate with each other.
In addition, the ring of the gas discharge portion 9a is arranged along a plane parallel to the surface of the wafer 20 placed on the wafer holder 12, and the plasma flowing from the upstream is narrowed to the central region by the magnetic field. Therefore, it easily passes through the center of the ring.

Further, the quartz tubes 22a and 22b of the gas discharge section 9a
A plurality of gas discharge holes penetrating the tube wall are formed along the inner circumference of the ring, and the second reaction gas is discharged onto the wafer 20 from these gas discharge holes. The gas discharge holes may be formed along the outer circumference of the ring, or may be formed along the lower part of the ring. However, it is not preferable to form along the upper part of the ring. This is because when the second reactive gas blows up above the gas releasing portion, the flowing plasma causes the second reactive gas to be activated above the gas releasing portion to form plasma into the first reactive gas. This is because the reaction product reacts with the second reaction gas to form a reaction product, which is attached to the gas releasing portion.

If the reaction products are unavoidably adhered to the quartz tubes 22a and 22b, the quartz tubes 22a and 22b are removed so that the reaction products do not peel off and fall onto the downstream wafer 20.
The contact area may be increased by forming irregularities on the surface of 22b. Further, the number and size of the gas release holes are appropriately adjusted depending on the type of the second reaction gas used. For example, TEOS
Is higher in viscosity than monosilane, so pores with a larger diameter are formed in the case of TEOS than in the case of monosilane.

As described above, the oxygen gas introduction pipe 8 and the T
By separating the EOS gas introduction pipe 9 from the reaction gas, the reaction between the reaction gases during the supply is prevented, and the generation of particles is suppressed. The film forming chamber 7 has a double structure of a chamber 7a made of metal such as quartz or aluminum and a protective wall 7b made of quartz or alumina.

The protection wall 7b is provided along the inner wall of the chamber 7a and can be detached separately from the chamber 7a. If necessary, it can be replaced with a new protective wall. The protection wall 7b is separated into an upper protection wall 71a and a lower protection wall 71b, and is made of cylindrical quartz or the like having different diameters. For example, the outer diameter of the upper protective wall 71a is smaller than the inner diameter of the lower protective wall 71b, so that the wafer holder 12 is lowered to the maximum and a slightly overlapping portion occurs, and the overlapping portion overlaps. Is set. This allows
When the wafer holder 12 is moved up and down together with the RF electrode 15, the wafer holder 12 is moved up and down in an overlapping state with the movement of the RF electrode 15. Further, the upper protective wall 71a is hung on the chamber 7a, and moves up and down with the movement when the chamber 7a is moved up and down. The protective wall 7b is provided with openings at locations corresponding to the insertion port, the exhaust port 11, and the wafer loading / unloading port 17 of the second reaction gas introduction pipe 9 of the chamber 7a.

The protection wall 7b prevents reaction products generated by the reaction of the reaction gas from adhering to the inner wall of the chamber 7a. That is, the reaction product adheres to the inner wall of the protective wall 7b. When cleaning the above protective wall 7b,
After the inside of the film forming chamber 7 is returned to the atmospheric pressure and the second reaction gas introducing pipe 9 is removed, the chamber 7 a is moved by the chamber lift 18.
Is moved to the upper part, and the upper protective wall 71a and the lower protective wall 71b are taken out. The upper protective wall 71a and the lower protective wall 71 taken out.
b is washed to remove the reaction products attached to the inner walls of the upper protective wall 71a and the lower protective wall 71b.

By setting another protective wall in place of the removed protective wall 7b, the film formation can be further continued in the CVD apparatus. Accordingly, it is not necessary to stop the CVD apparatus for a long time for cleaning the inside of the film forming chamber 7, and it is possible to maintain the throughput and reduce the labor and cost for maintenance. In some cases, the reaction product is etched by introducing an etching gas into the film forming chamber 7 without taking out the protective wall 7b.
It is also possible to perform -situ cleaning. Therefore, it is possible to prevent the chamber 7a from being damaged by the etching. Further, by providing a heating means around the chamber 7a and heating the protective wall 7b during the etching, the etching can be further promoted and the effect of in-situ cleaning can be improved.

Reference numeral 10 denotes a chamber solenoid provided around the film forming chamber 7 and formed of a cylindrical permanent magnet so that an appropriate magnetic field can be applied to the film forming chamber 7. Thereby, the plasma is guided from the plasma generation chamber 1 to the film formation chamber 7,
The flowing plasma is confined in the central region. Numeral 11 is for discharging unnecessary reaction gas and for generating plasma in the plasma generation chamber 1.
And an exhaust port to which an exhaust device is connected to reduce the pressure in the film forming chamber 7, and is provided in the film forming chamber 7.

Reference numeral 12 denotes a wafer holder (substrate holder) for mounting the wafer 20 provided below the film forming chamber 7, an electrostatic chuck for electrostatically fixing the wafer 20, and a heater for heating the wafer 20. And are built in a common insulating substrate.
Further, it is moved up and down by an up-down movement mechanism 12a. Next, the vertical moving mechanism 12 of the wafer holder 12
a will be described.

The ball screw 41 supporting the support plate 12b via a bearing support (not shown) is formed with teeth helically orbiting around an axis. The ball screw 41 is inserted into a ball nut 43 (not shown) provided on the fixing plate 12c, and meshes with the teeth of the ball screw 41 by the spirally formed teeth formed on the inner wall of the hole to support the ball screw 41. . The ball screw 41 is rotated by a stepping motor (not shown), and the support plate 12b and the RF electrode 15 are rotated.
The wafer holder 12 is moved up and down via.

An RF electrode 13 is provided below the wafer holder 12 in contact with the wafer holder 12, and has a frequency of 13.56M.
An RF power supply 15 that supplies power of Hz or 100 kHz is connected via a matching network 14. When a power of 13.56 MHz or 100 kHz is applied to the wafer 20, a negative self-bias DC voltage is applied to the wafer 20 to optimize the film quality such as the density and stress of the formed film.

Numeral 16 denotes a wafer lift pin, which is a vertical moving means.
The wafer 20 moves through the RF electrode 13 and the through-hole of the wafer holder 12 by 16a, pushes up the wafer 20, and separates the wafer 20 from the mounting surface of the wafer holder 12. Then, the separated wafer 20 is held by a wafer transfer tool or the like (not shown) and taken out from the wafer loading / unloading port 17.

Reference numeral 18 denotes a chamber lift which supports the flange 11a of the exhaust port 11 and moves the chamber 7a of the film forming chamber 7 up and down via the flange 11a. Chamber lift 1
Numeral 8 is formed with teeth that helically circulate around the ball screw, and meshes with the teeth of the ball screw by helically circulating teeth formed on the inner wall of the hole inserted into the ball nut to support the ball screw. As the ball screw rotates, the ball screw moves up and down, and moves the chamber 7a up and down via the flange 11a.

Reference numeral 50 denotes a floor on which the chamber lift 18 and the CVD device are mounted. As described above, in the CVD film forming apparatus according to the embodiment of the present invention, the external antenna 2 radiating the high-frequency power having a frequency of 13.56 MHz into the plasma generation chamber 1 and the magnetic field is formed within the plasma generation chamber 1. And inner and outer source solenoids 5,6. Therefore,
Helicon mode high-density plasma can be generated in the plasma generation chamber 1, and a dense film is formed.

Further, since the frequency of the high frequency power applied to the external antenna 2 is low at 13.56 MHz, there is no need for equipment such as a waveguide for generating a high frequency power of 2.45 GHz which is extremely high as in the case of the ECR type. Yes, the device configuration is simple. Further, a second reaction gas introduction pipe 9 is provided above the wafer 20 separately from the first reaction gas introduction pipe 8.
Therefore, it is possible to prevent the reaction gases from reacting with each other while supplying the reaction gas onto the wafer 20, and to suppress the generation of particles.

Further, since the gas discharge portion 9a of the second reaction gas introduction pipe 9 is disposed on the wafer 20, the reaction gas is uniformly supplied onto the wafer 20. For this reason, the uniformity of the film thickness is improved. Further, since the first reaction gas introduction pipe 8 communicates with the upstream central portion of the plasma generation chamber 1, the plasma generation efficiency is high. (2) Description of a gas introduction tool used in the film forming apparatus according to the second to sixth embodiments of the present invention (A) First reaction gas introduction pipe for introducing and discharging gas to be converted into plasma a) Second Embodiment FIG. 4 is a side view showing a first reaction gas introduction pipe according to a second embodiment of the present invention.

In FIG. 4, a first reaction gas introduction pipe (first gas introduction pipe) 8 for introducing and discharging a first reaction gas into the plasma generation chamber 1 has a gas discharge port at a pipe end. A 6 mm gas tube having an outer diameter of 6.35 mm and an inner diameter of 4 mm, which is inserted into the plasma generation chamber 1 from the upstream central portion of the chamber 1 a forming the plasma generation chamber 1, and its gas discharge port is provided. It is arranged so as to come to the center of the plasma generation chamber 1.

When the first reaction gas is introduced into the first reaction gas introduction pipe 8, the first reaction gas is discharged directly to the center of the plasma generation chamber 1. At this time, since a radio wave is radiated from the external antenna 2 and a magnetic field is applied from the solenoid coils 5 and 6, the first reaction gas is turned into plasma by receiving energy from an electromagnetic field. By the way, since the electric field and the magnetic field are distributed symmetrically, by introducing the reaction gas into the central portion of the plasma generation chamber 1, the first reaction gas is efficiently turned into plasma and the plasma generation efficiency is improved.

The plasma-converted first reaction gas flows downstream to activate the second reaction gas discharged into the film forming chamber 7. (B) Third Embodiment FIGS. 5A and 5B are a plan view and a side view showing a first reaction gas introduction pipe according to a third embodiment of the present invention.

5 (a) and 5 (b), a first reaction gas introduction pipe (first gas introduction pipe) 8 for introducing and discharging a first reaction gas into the plasma generation chamber 1 is a first reaction gas introduction pipe. Gas conduit (8th gas conduit) 8a having a plurality of gas discharge holes that guide the reaction gas of (3) and penetrate the tube wall, and the gas conduit 8a makes the tube axis perpendicular to the plate surface and makes the tube end face the plate surface. A relay plate 8b that is attached and receives the first reaction gas discharged from the gas discharge holes on the plate surface, and flows downstream beyond the edge of the plate surface.

When the first reactant gas is introduced into the gas conduit 8a, the first reactant gas flows through the gas conduit 8a and is introduced into the plasma generation chamber 1. Then, the gas is discharged into the plasma generation chamber 1 from the gas discharge holes formed in the tube wall. The released first reactant gas is partially turned into plasma and the other flows downstream. However, the movement toward the downstream is blocked by the relay plate 8b and spreads on the plate surface of the relay plate 8b, and moves to the peripheral portion of the plate surface. I do. At this time, radio waves are radiated from the external antenna 2,
In addition, since a magnetic field is applied from the solenoid coils 5 and 6, the first reaction gas is turned into plasma by receiving energy from an electromagnetic field. Due to the long travel distance, almost all of the reactant gas particles are turned into plasma during the travel.

Further, the plasma gas flows downstream beyond the edge of the plate surface, and activates the second reaction gas introduced into the film forming chamber 7. As described above, according to the first reaction gas introduction pipe according to the third embodiment of the present invention, the first reaction gas released from the gas conduit 8a is received by the relay plate 8b, and then the relay plate 8b is received. Since the moving distance of the reaction gas is lengthened by moving, the plasma can be promoted. This improves the plasma generation efficiency.

(B) A second reaction gas is introduced into the film forming chamber,
Second reaction gas introduction pipe for discharging In the second and third embodiments, the first reaction gas introduction pipe 8 for introducing and discharging the reaction gas into the plasma generation chamber 1.
However, in the following, in the fourth and fifth embodiments,
The second reaction gas introduction pipe 9 for introducing and releasing the second reaction gas into the film forming chamber 7 will be described.

(A) Fourth Embodiment FIGS. 7A and 7B are a plan view and a plan view showing a second reaction gas introduction pipe used in a film forming apparatus according to a fourth embodiment of the present invention. It is a side view. In FIGS. 7A and 7B, a second reaction gas introduction pipe (gas introduction tool) 9 for introducing and releasing the reaction gas into the film forming chamber 7 is a first gas conduit 21a for guiding the reaction gas. , Two second gas conduits 22c, 22c, communicating with the first gas conduit 21a and branching off from the first gas conduit 21a.
A second group of gas conduits comprising 22d. Each second
The gas conduits 22c and 22d are circulated in opposite directions from the branch point and formed in a ring shape. Further, the gas discharge section 9a
In the second gas conduits 22c and 22d, a plurality of gas discharge holes penetrating the tube wall are formed, for example, along the inner periphery of the ring.

Then, each of the second gas conduits 22c, 22d
The ring made of is arranged above the wafer 20 and along a plane parallel to the surface of the wafer 20. The second reaction gas is discharged from the gas discharge hole of the second reaction gas introduction pipe onto the wafer 20 placed on the wafer holder 12. The released second reaction gas is turned into plasma, activated by the first reaction gas flowing downstream, and reacts with the first reaction gas. As a result, the wafer 20 is produced as a reaction product.
An insulating film or the like is formed on top.

As described above, the second embodiment described in the first embodiment
It is possible to obtain the same effect as that of the reaction gas introduction pipe 9 described above. (B) Fifth and Sixth Embodiment FIGS. 8A and 8B are a plan view and a plan view showing a second reaction gas introduction pipe used in a film forming apparatus according to a fifth embodiment of the present invention. It is a side view.

8 (a) and 8 (b), a second reaction gas introduction pipe (gas introduction tool) 9 communicates with a third gas conduit 21b for guiding the reaction gas and the third gas conduit 21b. , Two fourth gas conduits 23a branched from the third gas conduit 21b,
It has a fourth gas conduit group consisting of 23b and a fifth gas conduit group consisting of a set of fifth gas conduits 22e and 22f communicating with the respective fourth gas conduits 23a and 23b. The fifth gas conduit group is formed in a ring shape.

In each of the fifth gas conduits 22e and 22f, a plurality of gas discharge holes penetrating the tube wall are formed, for example, along the inner circumference or the outer circumference of the ring. The ring formed by the fifth group of gas conduits is
0 and along a plane parallel to the surface of the wafer 20. The reaction gas is discharged from the gas discharge hole of the second reaction gas introduction pipe 9 onto the wafer 20 placed on the wafer holder 12. The released second reaction gas is turned into plasma, activated by the first reaction gas flowing downstream, and reacts with the first reaction gas. As a result, an insulating film or the like is formed on the wafer 20 as a reaction product.

As described above, the second embodiment described in the first embodiment
It is possible to obtain the same effect as that of the reaction gas introduction pipe 9 described above. In the fifth embodiment, the fifth gas conduit group, which is the gas discharging portion 9a, has the gas conduits 22e and 22f separately separated from each other, but the fifth gas conduit group shown in FIGS. 9 (a) and 9 (b). As in the sixth embodiment, if desired, the gas conduits 22g, 22h may be reunited at the tube ends to form a ring in which the internal passages of the gas conduits 22g, 22h communicate with each other.

Further, in the above fourth to sixth embodiments, the gas discharge holes are provided along the inner circumference of the ring of the gas conduit of the gas discharge portion 9a, but gas is discharged along the outer circumference and the lower portion of the ring. Pores may be formed. (3) Description of a film forming method by a CVD method using helicon mode plasma according to an embodiment of the present invention Next, formation of a silicon oxide film according to an embodiment of the present invention using the CVD film forming apparatus of FIG. The method will be described. O ₂ + TEOS (Ar) gas is used as a reaction gas. TE
OS (Ar) gas is obtained by bubbling in a TEOS solution at room temperature using Ar gas as a carrier gas. Note that TEOS is Si (OC ₂ H ₅ ) ₄ (SiO ₄ C ₈ H _20,
4 ethoxysilane).

The conditions for film formation are as follows: (a) O ₂ / TEOS (Ar) flow rate ratio (standard value = 3) (b) Total flow rate of reaction gas (O ₂ = 1.31 SLM, TEOS (A
r) = 0.44 SLM, standard value = 1.75 SLM) (c) Gas pressure (standard value = 0.2 Torr) (d) Substrate temperature (standard value = 350 ° C) (e) Wafer position (the lower end of the film forming chamber 7 is zero) The upper side is positive and the lower side is negative. Standard value = + 45 mm) (f) RF power applied to the external antenna 2 (standard value = 1.5
kW) (g) Inner solenoid current (standard value = 50A) (f) Outer solenoid current (standard value = 60A)

Incidentally, it is also possible to use O ₂ + SiH ₄ gas as the reaction gas. In this case, an example of the film forming conditions will be described below. (a) O ₂ / SiH ₄ flow ratio (standard value = 1) (b) Reactant gas flow and total gas flow (O ₂ gas flow standard = 30 SCCM, SiH ₄ gas flow standard = 30 SCCM, total gas flow standard (Value = 60 SCCM) (c) Gas pressure (standard value = 20 mTorr) (e) Wafer position (the lower end of the film forming chamber 7 is set to zero, and a position above this is shown. Standard value = 161 mm) (f) Substrate bias [ P _B ] (frequency standard value = 100kHz
, Power standard value = 200 W) (g) RF power [P _RF ] applied to the external antenna 2 (frequency standard value = 13.56 MHz, power standard value = 1.0 kW) (h) Inner source solenoid current [I _IS ] (standard Value = 50
A) (i) Outer source solenoid current [ _IOS ] (standard value = 60)
A) First, the wafer 20 is placed on the wafer holder 12 and fixed by an electrostatic chuck, and then the plasma generation chamber 1 and the film formation chamber 7 are evacuated by a turbo molecular pump and kept at 10 ⁻³ Torr or less.

Next, the wafer holder 12 on which the wafer 20 is placed is moved upward, and is placed at a predetermined position in the film forming chamber 7. Subsequently, the wafer 20 is heated by a heater (not shown) built in the wafer holder 12 to maintain the wafer 20 at a predetermined temperature. Next, a predetermined flow rate of O ₂ gas is introduced into the plasma generation chamber 1 through the first reaction gas introduction pipe 8, and a predetermined flow rate of T ₂ gas is supplied through the second reaction gas introduction pipe 9.
EOS (Ar) gas or SiH ₄ gas is introduced into the film forming chamber 7. Subsequently, the gas pressure in the film forming chamber 7 is adjusted and maintained at a predetermined pressure.

Next, a predetermined current is applied to the inner and outer source solenoids 5 and 6 to generate a magnetic field, and a predetermined RF power is applied to the external antenna 2 via the matching network 3. This allows O ₂
The gas is activated and helicon mode plasma is generated. Further, this helicon mode plasma flows into the film forming chamber 7 and the TEOS gas is activated. Subsequently, the activated TEOS gas reacts with the oxygen plasma to start depositing a silicon oxide film on the wafer 20 at a predetermined deposition rate.

By maintaining this state for a predetermined time, a silicon oxide film having a predetermined thickness is formed on the wafer 20. As described above, in the film forming method according to the embodiment of the present invention, the helicon mode plasma composed of the first reaction gas is generated by the high frequency power of 13.56 MHz and the magnetic field, and further activated by the plasma. Second
A film is formed on the substrate together with the reaction gas. Since the helicon mode plasma has a high density, the denseness of the formed film is improved.

[0054]

As described above, in the film forming apparatus according to the present invention, the first gas introduction tool communicates with the chamber forming the plasma generation chamber in the upstream central portion of the plasma generation chamber, or plasma generation is performed. Since it is arranged at the center of the chamber, the plasma generation efficiency is good.

Further, since the released first reaction gas is received by the relay plate and moved on the relay plate, the residence time in the plasma generation part is lengthened, so that the plasma generation efficiency is improved. Further, since the gas releasing portion of the gas introducing tool is arranged on the substrate, the reaction gas is uniformly supplied on the substrate, and thus the uniformity of the film thickness is improved.

Further, since the gas releasing portion is formed in a ring shape, the plasma flowing from the upstream of the film forming portion easily passes. As a CVD apparatus equipped with the first gas introduction tool and the gas introduction tool described above, a frequency of 13.56 M was set in the plasma generation unit
C having an external antenna that radiates high-frequency power of 1 Hz and a source solenoid that forms a magnetic field in the plasma generation unit
A VD device is used. Therefore, helicon mode high-density plasma can be generated in the plasma generation unit, and a highly dense film is formed.

Further, since the frequency of the high frequency power applied to the external antenna is 13.56 MHz, the equipment such as a waveguide for generating the high frequency power of 2.45 GHz, which is extremely high as in the case of the ECR type, is unnecessary. The device configuration is simple. Further, a gas introduction tool is provided above the substrate separately from the first gas introduction tool. Therefore, the reaction gases can be prevented from reacting with each other during the supply of the reaction gas onto the substrate, and the generation of particles can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view showing a CVD film forming apparatus using helicon mode plasma according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing details of an external antenna used in a CVD film forming apparatus using helicon mode plasma according to the embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a solenoid current and a vertical magnetic field in a CVD film forming apparatus using helicon mode plasma according to an embodiment of the present invention.

FIG. 4 is a side view showing a first reaction gas introduction pipe used in a CVD film forming apparatus using helicon mode plasma according to a second embodiment of the present invention.

FIG. 5 is a side view and a plan view showing a first reaction gas introduction pipe used in a CVD film forming apparatus using helicon mode plasma according to a third embodiment of the present invention.

FIG. 6 is a side view and a plan view showing a second reaction gas introduction pipe used in a CVD film forming apparatus using helicon mode plasma according to the first embodiment of the present invention.

FIG. 7 is a side view and a plan view showing a second reaction gas introduction pipe used in a CVD film forming apparatus using helicon mode plasma according to a fourth embodiment of the present invention.

FIG. 8 is a side view and a plan view showing a second reaction gas introduction pipe used in a CVD film forming apparatus using helicon mode plasma according to a fifth embodiment of the present invention.

FIG. 9 is a side view and a plan view showing a second reaction gas introduction pipe used in a CVD film forming apparatus using helicon mode plasma according to a sixth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 plasma generation chamber (plasma generation section), 1a, 7a chamber, 2 external antenna, 3,13 matching network, 4,14 RF power supply, 5 inside source solenoid, 6 outside source solenoid, 7 film formation chamber (film formation section) , 7b protective wall, 7c, 15a seal portion, 8 first reaction gas introduction pipe (sixth gas introduction pipe), 9 second reaction gas introduction pipe (gas introduction tool), 9a gas discharge section, 10 chamber solenoid , 11 exhaust port, 11a flange, 12 wafer holder, 12a vertical moving mechanism, 15 RF electrode, 16 wafer lift pin, 17 wafer loading / unloading port, 18 chamber lift (vertical moving means), 20 wafer (substrate), 21a , 21b, 22a to 22h, 23a, 23b Gas conduit, 41 ball screw, 43 ball nut, 50 floor, 71a upper protection wall, 71b lower protection Guard wall, 72 bellows.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Koichi Ohira 2-13-29 Konan, Minato-ku, Tokyo Inside Semiconductor Process Research Laboratories (72) Inventor Yuko Nishimoto 2-13-29 Konan, Minato-ku, Tokyo (56) References JP-A-4-287309 (JP, A) JP-A-62-254419 (JP, A) JP-A-2-294491 (JP, A) JP-A-2- 114530 (JP, A) Nikkei Micro Device, October 1991 (No. 76), pp. 94-95

Claims (2)

(57) [Claims] 1. A first gas introduction pipe guides a first reaction gas to a plasma generation unit to generate plasma, and a second gas introduction pipe guides a second reaction gas to a film formation unit to generate the plasma. In the film forming apparatus for activating the second reaction gas to form a film on a substrate, the first gas introducing pipe includes a gas conduit having a plurality of gas discharge holes in a pipe wall, and the gas. It is attached to the end of the gas conduit, which receives the first reaction gas discharged from the discharge hole on the plate surface, guides it from the plate surface to the edge of the plate surface, and then flows it to the film forming unit downstream. And a relay plate. 2. The second gas introduction pipe is ring-shaped and has a plurality of gas discharge holes along a pipe wall of the ring, and is located below the relay plate in parallel with the relay plate. The film forming apparatus according to claim 1, wherein: