JP3214092B2 - Semiconductor device manufacturing method and semiconductor manufacturing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device and a semiconductor manufacturing apparatus, particularly a rapid heating apparatus.

[0002]

2. Description of the Related Art Attention has been paid to a nitride oxide film as an insulating film of a next-generation semiconductor device, for example, a gate insulating film or a dielectric film of a capacitor. Conventionally, this nitrided oxide film is formed as follows.

As shown in FIG. 11A, a thermal oxidation process is performed on the surface of a silicon substrate 1 in an oxygen (O ₂ ) atmosphere to form a thermal oxide film (SiO ₂ ) 2, and then as shown in FIG. 11B. Then, the thermal oxide film 2 is nitrided in an ammonia (NH ₃ ) atmosphere to form a nitrided film 3. Then, as shown in FIG. 11C, the thermal oxide film 2 is again heated at a high temperature of 1050 ° C. or more in an oxygen (O ₂ ) atmosphere. An oxidation process is performed to form a silicon oxynitride film 4. The nitriding treatment and the reoxidation treatment are performed by rapid lamp heating. The reason for performing the re-oxidation treatment is to recover the defects generated by the nitridation treatment by oxidation (see Japanese Patent Application Laid-Open No. 3-4557).

As a method of forming a silicon nitride oxide film, for example, SiH ₄ gas, N ₂ O gas, NH ₃ gas and N
There is also known a method of performing vapor phase growth by light irradiation in an atmosphere in which _two gases coexist (Japanese Unexamined Patent Publication No. 3-225828).
No.).

On the other hand, as a heat treatment apparatus used in a manufacturing process of a semiconductor device, for example, the above-described nitriding treatment, reoxidation treatment, etc., for example, a rapid lamp heating device 11 as shown in FIG. 12 is known. In this apparatus 11, a quartz tray 14 for supporting a semiconductor wafer 13 is arranged in a quartz chamber 12, and a plurality of, for example, tungsten halogen lamps 15 as light irradiation sources are arranged on both upper and lower sides of the chamber 12. Reference numeral 16 denotes a light reflection plate. Further, a first infrared radiation thermometer 17 that detects infrared radiation from the semiconductor wafer 13 through the transmission window 18 of the chamber 12 to detect a heating temperature of the semiconductor wafer 13 is disposed below the chamber 12, A second infrared radiation thermometer 19 for detecting the temperature of the chamber 12 is arranged alongside this. The true heating temperature of the semiconductor wafer 13 is measured based on the difference between the measurement values of the first and second infrared radiation thermometers 17 and 19.

[0006] As shown in FIGS. 13 and 14, the tray 14 has an opening 21 sufficient for the semiconductor wafer 13 to be arranged.
A quartz tray main body 22 having three, a holding portion 23 extending from the tray main body 22 to the opening 21 and having a tip bent upward, and a ring-shaped body 2 surrounding the semiconductor wafer 13.
4 The semiconductor wafer 13 is mounted on the tips of the three holding portions 23, and is configured such that heat dissipation from the periphery of the semiconductor wafer 13 during heating is prevented by the ring-shaped body 24.

In this rapid lamp heating device 11, the lamp is rapidly heated by lamp light from tungsten halogen lamps 15 on both upper and lower sides while being placed on a tray 14 in a quartz chamber 12. And the semiconductor wafer 13
Is detected by the infrared radiation thermometers 17 and 19.

[0008]

In the conventional manufacturing method for forming a nitrided oxide film through the above-described three steps of thermal oxidation, nitridation, and re-oxidation, oxygen (O ₂ The reoxidation performed in the atmosphere must be performed by a high temperature treatment of 1050 ° C. or more. However, in a next-generation semiconductor device aiming at a shallow PN junction, high-temperature processing leads to re-diffusion of the junction, which is an obstacle. The conventional reoxidation treatment in an oxygen atmosphere has a problem that the treatment temperature must be high as described above.

[0009] On the other hand, in rapid thermal apparatus used as a heating device shown in FIG. 12 is for rapidly heating the semiconductor wafer 13 by the lamp light L ₁ from the lamp 15, the aluminum on the surface of the semiconductor wafer 13 some of the lamp light L ₁ in a case where the light reflection film having a film such as is present is reflected by the aluminum film or the like, etc. reflected by the light reflection plate 16, the reflected light L ₂ to repeat the reflections of the chamber 12 It may be incident on the infrared radiation thermometer 17 on the back surface. If the reflected light L ₂ is incident, it will be the output of the infrared radiation thermometer 17 is varied by the intensity of the light,
There is a possibility that the temperature of the semiconductor wafer 13 cannot be detected accurately.

The present invention has been made in view of the above circumstances, and provides a method of manufacturing a semiconductor device capable of forming a nitrided oxide film having a long film life with a reduced reoxidation treatment temperature.

Another object of the present invention is to provide a rapid heating apparatus with a reduced temperature detection error, that is, a semiconductor manufacturing apparatus.

[0012]

According to the present invention, a semiconductor substrate is provided.
In the step of forming a nitrided oxide film 34 by nitriding and reoxidizing the thermal oxide film 32 formed on the substrate 1 by the thermal oxidation process, the reoxidation process is performed in an N ₂ O atmosphere.

In the re-oxidation treatment, the re-oxidation treatment is performed by light irradiation heating using a halogen lamp beam, an excimer laser or another laser.

The reoxidation temperature is 850 ° C.
It is performed at a processing temperature of less than -1050 ° C.

Further, the present invention includes a chamber 41, a supporting jig 48 of the semiconductor wafer 13 disposed in the chamber 41, a light radiation source 43 with respect to the semiconductor wafer 13 disposed outside the chamber 41, the chamber 41 Infrared radiation thermometer for detecting the temperature of the semiconductor wafer 13 disposed outside
44 , the semiconductor wafer 1
The support jig 48 of No. 3 is formed of a member that absorbs the light L ₂ from the light irradiation source 43 and reflects the light from the light irradiation source 43.
To block the optical path incident on the infrared radiation thermometer 44
To be configured.

As a jig 48 for supporting a semiconductor wafer, S
It can be composed of an iC member or a carbon member coated with SiC.

[0017]

In the manufacturing method according to the present invention, in the step of forming a nitrided oxide film by performing a thermal oxidation treatment-nitridation treatment-reoxidation treatment,
By performing the re-oxidation treatment in an N ₂ O atmosphere, the processing temperature of the re-oxidation treatment can be set to a lower temperature than in the past. In addition, the defect density can be reduced and the life can be extended as compared with the conventional nitrided oxide film.

Further, by performing light irradiation heating as the heat treatment in the reoxidation treatment, rapid heating is performed and so-called re-diffusion of a shallow junction is prevented.

Further, the reoxidation treatment is performed at a treatment temperature of 850.
C. to less than 1050.degree.
Can be prevented from deteriorating.

Further, in the semiconductor manufacturing apparatus of the present invention, the support jig 48 of the semiconductor wafer 13 is formed of a member capable of absorbing light from the light irradiation source, and
Blocks the optical path where light is reflected and enters the infrared radiation thermometer 44
By the placed such that, when the reflective layer such as aluminum is heat treated in a state of being formed on a semiconductor wafer surface, light from the light radiation source 43 is irradiated to the infrared radiation thermometer 44 is reflected However, the reflected light L ₂ is prevented from being incident on the infrared radiation thermometer 44 by the support jig 48. Therefore, the infrared radiation thermometer 44 can accurately detect the temperature of the semiconductor wafer.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a method for forming a nitrided oxide film according to the present invention. In this example, first, as shown in FIG. 1A, the surface of the silicon substrate 31 is subjected to a thermal oxidation treatment in an oxidizing atmosphere, for example, an oxygen (O ₂ ) atmosphere by using, for example, a diffusion furnace to form a thermal oxide film (SiO ₂ film). 32 are formed.

Next, the rapid lamp heating device 4 shown in FIG.
0, ammonia (NH ₃ ) as shown in FIG.
Heat treatment (for example, rapid lamp heating at a temperature of 1050 ° C. for 60 seconds) in an atmosphere, that is, a nitriding treatment is performed. This allows
The silicon substrate 31 and the thermal oxide film 32 are nitrided, and the thermal oxide film 32 becomes a nitriding film 33.

Next, as shown in FIG. 1C, in the same rapid thermal annealing apparatus 40, by introducing the N ₂ O gas, the N ₂ O
850 ° C. to less than 1050 ° C., preferably 100
A re-oxidation process is performed by heating at 0 ° C. to finally form a silicon oxynitride film 34. Processing time for reoxidized film is 6
It is about 0 seconds.

The rapid lamp heating device 40 of FIG. 2 used in the present embodiment is configured in the same manner as described above,
1 and a semiconductor wafer 1 disposed in the chamber 41
And a plurality of tungsten halogen lamps 43 arranged on both upper and lower sides of the chamber 41.
And the semiconductor wafer 13 disposed below the chamber 41
And a second infrared radiation thermometer 45 for detecting the temperature of the chamber 41. Reference numeral 46 denotes a light reflector disposed on the lamp 43. In this apparatus 40, a required gas 47 is introduced from one inlet 42A of the chamber 41, and the semiconductor wafer 13 is rapidly irradiated by irradiating a lamp beam from a tungsten halogen lamp 43 in a state where the inside of the chamber 41 is in a predetermined atmosphere. It is made to heat.

According to the method of forming a nitrided oxide film of this embodiment, the reoxidation is performed in an N ₂ O atmosphere, thereby reducing the processing temperature to 850 ° C. to 10 ° C., which is lower than the conventional temperature.
It can be performed at less than 50 ° C. Further, the nitrided oxide film 34 formed by this manufacturing method is
As compared with (see FIG. 11), the defect density can be reduced and the life of the film can be extended.

Next, the characteristics will be described. As shown in FIG. 3, polycrystalline silicon is deposited on the nitrided oxide film 34 obtained in the above embodiment by a CVD method, phosphorus (P) is diffused by a thermal diffusion method, and then photolithography and RIE (reaction) are performed. The polycrystalline silicon electrode 36 is formed by patterning using the technique of (active ion etching). A constant current (current density 100) is applied between the polycrystalline silicon electrode 36 and the silicon substrate 31.
FIG. 4 shows the results obtained by measuring the time until the nitrided oxide film 34 breaks when mA / cm ² is passed, that is, the so-called TDDB (time-dependent dielectric breakdown) resistance.

FIG. 4 shows that 10% O _{2 is} deposited on a silicon substrate.
A thermal oxide film is formed at a temperature of 1000 ° C. in a 90% N ₂ atmosphere, and at a temperature of 1050 ° C. and 60% in a 100% NH ₃ atmosphere.
Nitrided oxide film after nitriding by lamp heating for ₂ seconds and reoxidized by lamp heating in O ₂ atmosphere (in the case of conventional example)
And a nitrided oxide film (the present invention) re-oxidized by lamp heating in an N ₂ O atmosphere after nitriding. △ indicates a conventional nitrided oxide film at a reoxidation treatment temperature of 1000 ° C, □ indicates a conventional nitrided oxide film at a reoxidation treatment temperature of 1150 ° C, and ● indicates a reoxidation treatment temperature of 1000.
5C is a nitrided oxide film according to the method of the present invention at ℃. Each processing time is 60 seconds.

Although not shown, if there is no reoxidation treatment, the cumulative failure rate is 70% or more with a stress time of 1 second, and the film quality is very poor. As shown in FIG. 4, when the reoxidation is performed, the life of the film is extended, and as can be seen from the marks Δ and □, the life of the film is extended by increasing the reoxidation processing temperature. That is, the quality of the film is significantly improved by performing the re-oxidation. In the case of reoxidation in an O ₂ atmosphere, the time at which the reoxidation treatment temperature is 1150 ° C. is the longest and the cumulative failure rate is 50% is 450 seconds.

A comparison between the conventional method and the method of the present invention shows that when the re-oxidation treatment temperature is the same at 1000 ° C. and when the re-oxidation treatment is carried out in the conventional O ₂ atmosphere (△ mark).
When re-oxidized in N ₂ O atmosphere (marked with ●)
Has a longer lifespan.

When the reoxidation treatment is performed in an N ₂ O atmosphere, the reoxidation treatment is performed at a processing temperature of 1000 ° C. (see ● marks), which is about the same as the reoxidation treatment at 1150 ° C. in a conventional O ₂ atmosphere (see □ marks). Life is obtained. That is, by performing the re-oxidation treatment in the N ₂ O atmosphere, the processing temperature can be reduced by about 150 ° C. as compared with the case of performing the re-oxidation treatment in the conventional O ₂ atmosphere.

On the other hand, lowering the reoxidation temperature during the formation of the nitrided oxide film than before is very effective in preventing the breakdown voltage of the bulk gate from deteriorating. FIG. 5 is a correlation diagram of gate breakdown voltage degradation due to heat treatment conditions after gate formation. That is, it shows the breakdown voltage ratio of the gate insulating film when a polycrystalline silicon gate electrode is formed on the gate insulating film made of the nitrided oxide film and then heat-treated.

When this heat treatment is applied to the formation of a DRAM, it is considered that it corresponds to the heat treatment after the formation of the MOS transistor, for example, the processing temperature of the re-oxidation treatment at the time of forming the nitrided oxide film to be the dielectric film of the capacitor. May be.

As shown in FIG. 5, the defect rate increases from 1050 ° C., and the heat treatment at 1150 ° C. causes a large deterioration in the breakdown voltage of the nitrided oxide film as the gate insulating film. 1050 ° C
If the temperature is less than 1000 ° C., no deterioration occurs.

[0035] Consequently, by changing the reoxidation treatment at the time of forming the oxynitride film from O ₂ atmosphere N ₂ O atmosphere, it is possible to reduce the processing temperature from 1150 ° C. to 1000 ° C.. That is, for example, when a nitrided oxide film is applied as a dielectric film of a capacitor of a DRAM, the temperature of the re-oxidation process at the time of forming the dielectric film is set to 1000 ° C., which is the same as that formed at 1150 ° C. in the related art. At the same time, it is possible to obtain a sufficient film quality, and the withstand voltage of the gate insulating film (that is, the nitrided oxide film) of the already formed MOS transistor is not affected by the heat treatment of the reoxidation process.

In the above example, the rapid heating at the time of the re-oxidation treatment was performed by irradiating a lamp light from a halogen tungsten lamp. However, excimer laser light irradiation heating, other laser light irradiation heating, or the like may be used. It is.

In the above example, the thermal oxide film is formed using a diffusion furnace in view of the uniformity of the thermal oxide film thickness.
It is also possible to form using the rapid lamp heating device of FIG.

FIG. 6 shows an embodiment of a rapid heating apparatus according to the present invention, that is, a rapid lamp heating apparatus. In the figure,
Reference numeral 41 denotes a quartz chamber, and reference numeral 48 denotes a support jig or tray for supporting the semiconductor wafer 13 arranged in the quartz chamber 41. Reference numeral 43 denotes a tungsten halogen lamp disposed on both the upper and lower sides of the chamber 41; 46, a light reflecting plate; 44, a first infrared radiation thermometer for detecting the temperature of the semiconductor wafer 13 through the transmission window 41a; 41 shows an infrared radiation thermometer for detecting the temperature of 41. In this example, the tray 48 supporting the semiconductor wafer 13 is formed of a member that absorbs light from the lamp 43, for example, a SiC member. The SiC tray 48 has a low transmittance of infrared light and substantially cuts infrared light.

As shown in FIG. 7, the SiC tray 48 has an SiC substrate 50 having a flat plate-like shape, an opening 49 larger than the semiconductor wafer 13 formed in the center thereof, and a slit formed therein. The semiconductor silicon wafer 13 is provided at a plurality of positions on the peripheral portion sandwiching the opening 49, in this example, at three positions.
Is provided. Holder 5
As shown in FIG.
Quartz support pin 5 supported by point contact so as to extend into 9
3. A plurality of legs 54 are provided on the back surface of the SiC substrate 50. 9 and FIG.
As shown in FIG.
Is placed on the tip of the support pin 53 so as to be stored in the opening 49.

According to the apparatus having such a configuration, the tray 48 supporting the semiconductor wafer 13 is formed of a tray made of, for example, SiC which absorbs the light from the tungsten halogen lamp 43, and as shown in FIG.
Light L ₁ is also about to be incident on the infrared radiation thermometer 44 surface and the reflected light L ₂ is reflected by the light reflection plate 46 of the chamber lower part semiconductor wafer 13 from its SiC
The reflected light L ₂ is absorbed by the tray 48. Therefore, the reflected light L ₂ is capable of detecting a temperature of the first infrared radiation thermometer 44 rather than being incident to accurately semiconductor wafer 13 for detecting the temperature of the semiconductor wafer 13.

Further, since the tray 48 of this embodiment supports the semiconductor wafer 13 so as to be accommodated in the opening 49, even when the semiconductor wafer 13 is heated, heat may escape from the periphery of the semiconductor wafer 13. With 50, heat radiation from the semiconductor wafer 13 can be prevented. This doubles as the ring 24 conventionally provided for that purpose, and can be structurally simplified.

In the above example, the tray 48 is S
Although the iC substrate 50 is used, a carbon substrate coated with SiC may be used.

[0043]

According to the manufacturing method of the present invention, it is possible to reduce the processing temperature of the reoxidation treatment by rapid heating in forming a nitrided oxide film as compared with the conventional method. In addition, the nitrided oxide film can reduce the defect density and extend the life as compared with the related art.

According to the semiconductor manufacturing apparatus of the present invention, when a semiconductor wafer is irradiated with light from a light irradiation source and subjected to heat treatment, reflected light that is reflected on the surface of the semiconductor wafer and is repeatedly reflected is reflected on the semiconductor wafer. The temperature of the semiconductor wafer can be accurately detected without being incident on an infrared radiation thermometer for detecting the temperature of the semiconductor wafer, which is absorbed by the supporting jig for supporting the semiconductor wafer.

[Brief description of the drawings]

FIG. 1 is a process chart showing a step of forming a nitrided oxide film of the present invention.

FIG. 2 is a configuration diagram showing an example of a rapid lamp heating device used in the manufacturing method of the present invention.

FIG. 3 is a cross-sectional view of a gate structure serving as a sample for property measurement according to the present invention.

FIG. 4 is a graph showing TDDB (time-dependent dielectric breakdown) resistance of a nitrided oxide film obtained by the present invention.

FIG. 5 is a characteristic diagram showing gate breakdown voltage degradation due to heat treatment conditions when a nitrided oxide film is used as a gate insulating film.

FIG. 6 is a configuration diagram illustrating an example of a rapid heating apparatus according to the present invention.

FIG. 7 is a perspective view showing an example of a tray according to the present invention.

8 is an enlarged perspective view of the holder of FIG.

FIG. 9 is a plan view of a tray according to the present invention in a state where a semiconductor wafer is supported.

FIG. 10 is a side view of FIG. 9;

FIG. 11 is a process chart showing a conventional step of forming a nitrided oxide film.

FIG. 12 is a configuration diagram of a conventional rapid lamp heating device.

FIG. 13 is a plan view showing a conventional tray.

FIG. 14 is a side view of FIG.

[Explanation of symbols]

 1,31 silicon substrate 2,32 thermal oxide film 3,33 nitridation film 4,34 nitride oxide film 13 semiconductor wafer 12,41 quartz chamber 14,42,48 tray 15,43 halogen tungsten lamp 17,19,44,45 Infrared radiation thermometer 16,46 Light reflector

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-199672 (JP, A) JP-A-63-246829 (JP, A) JP-A-62-296512 (JP, A) JP-A-2- 98128 (JP, A) JP-A-3-257828 (JP, A) JP-A-3-244125 (JP, A) JP-A-3-278576 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) H01L 21/318 H01L 21/31

Claims (5)

(57) [Claims] In a step of forming a nitrided oxide film by nitriding and reoxidizing a thermal oxide film formed on a semiconductor substrate by a thermal oxidation process, the reoxidation process is performed in an N ₂ O atmosphere. Characteristic semiconductor device manufacturing method. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the re-oxidation treatment is performed by light irradiation heating. 3. The method according to claim 1, wherein the re-oxidation is performed at a processing temperature of 850 ° C. to less than 1050 ° C. 4. A chamber, a jig for supporting a semiconductor wafer disposed in the chamber, a light irradiation source for the semiconductor wafer disposed outside the chamber, and a light source for irradiating the semiconductor wafer disposed outside the chamber. In a semiconductor manufacturing apparatus provided with an infrared radiation thermometer for temperature detection, a jig for supporting the semiconductor wafer is formed of a member that absorbs light from the light irradiation source, and light from the light irradiation source is
Blocks the optical path that reflects and enters the infrared radiation thermometer
Semiconductor device arranged as follows. 5. The semiconductor manufacturing apparatus according to claim 4, wherein the jig for supporting the semiconductor wafer is made of a SiC member or a SiC-coated carbon member.