JP2636817B2 - Single wafer type thin film forming method and thin film forming 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 thin film forming apparatus and a thin film forming apparatus used therefor, and more particularly to a thin film forming method and a thin film forming apparatus suitable for forming a thin film having good characteristics with good controllability.

[0002]

2. Description of the Related Art In the formation of a thin film, the conventional thermal oxidation method of lithicon has been carried out using an ordinary electric furnace. With the recent miniaturization of semiconductor devices, thinner silicon oxide films have become necessary. However, in conventional thermal oxidation using an electric furnace, a thin oxide film was formed by lowering the oxidation temperature and lowering the oxygen partial pressure. ing. According to such a method, a silicon oxide film of several nm can be easily formed.

In a conventional gas phase chemical reaction method for forming a thin film, a reaction gas is introduced into a reaction vessel, and a thin film is deposited on a sample surface in a high-temperature gas atmosphere. According to this method, various thin films having various characteristics can be formed by selecting a reaction gas species and reaction conditions.

[0004]

However, when a silicon oxide film is formed on the surface of a polycrystalline silicon film by lowering the oxidation temperature, the dependence of the oxidation rate on the plane orientation is emphasized, and the formation of the silicon oxide film on the surface of the polycrystalline silicon film is emphasized. There is a problem that the thickness of the silicon oxide film becomes uneven.

In the case of forming phosphorus glass by the above method, in a high-temperature atmosphere, almost all of the reaction occurs near the introduction of the reaction gas into the reaction vessel, and the phosphorus concentration in the phosphorus glass formed on the sample surface cannot be controlled. It is necessary to carry out the reaction in a low temperature atmosphere. Therefore, a high-temperature annealing treatment for densification of the formed phosphorus glass film is required. In addition, the low-temperature reaction has a problem that the step coverage of the step portion is poor. Therefore, it is not possible to form a fine step-coverage phosphorus glass, and to slightly form non-stop SiO glass.
₂ can be deposited.

Further, when a polycrystalline silicon film is formed on the surface of a silicon substrate, if a conventional reactor of an electric furnace is used, the ambient atmosphere (mainly from the furnace port) when a sample enters and exits the furnace. Mixed with air), the surface of the silicon substrate is oxidized, so that the interface between the polycrystalline silicon film and the silicon substrate cannot be kept clean. As a result, there arises a problem that electrical conduction at the interface becomes incomplete.

When a lamp house as a heating source is provided around the reaction vessel, stress is applied to the reaction vessel due to a difference in the degree of vacuum between the reaction vessel and the lamp house, and the reaction vessel is distorted or damaged. In some cases.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional method, to form a thin film having good characteristics with good controllability, to facilitate a thin film forming process, and to provide a strain in a reaction vessel. It is an object of the present invention to provide a thin film forming apparatus and a thin film forming apparatus which are free from damage or damage.

[0009]

Means for Solving the Problems The degree of vacuum inside the reaction vessel and inside the lamp house is made substantially the same, and
This is achieved by forming a film in the first atmosphere by controlling the temperature to the above temperature, and then controlling the temperature to the second temperature in the order of seconds and performing the sample processing in the second atmosphere.

[0010]

By making the degree of vacuum inside the reaction vessel and the inside of the lamp house substantially the same, the stress applied to the reaction vessel is reduced, and the occurrence of distortion and breakage can be prevented.

Next, the thermal oxidation method of silicon will be described. In the thermal oxidation of silicon, the oxidation rate strongly depends on the plane orientation of silicon, for example, (110)>(111)>
(100). The plane orientation dependence of the oxidation rate decreases as the temperature increases. Therefore, in the surface oxidation of a polycrystalline silicon film having crystal grains of various plane orientations, uniform oxidation can be achieved by increasing the oxidation temperature.

A thinner silicon oxide film is required as the semiconductor device becomes finer. However, in the present invention, a thinner silicon oxide film is formed by shortening the oxidation time by increasing the oxidation temperature. Do. The oxidation time is on the order of seconds, and even in such a short-time oxidation, there is an effect of the above-described plane orientation-dependent oxidation temperature.

Next, formation of a thin film by a gas phase chemical reaction method will be described. In the above reaction method, the temperature relationship between the reaction vessel, the reaction gas, and the sample is represented by (sample)> (reaction gas)>
In the order of (reaction vessel), most of the reaction of the reaction gas species introduced into the reaction vessel occurs near the sample surface.
In addition, the temperature of the reaction vessel is set to 200 ° C. or less. For example, when forming the above-mentioned phosphorus glass, heating only the sample in a state where the controlled reaction gas species is introduced into the reaction vessel can cause a reaction only in the vicinity of the sample, so that the phosphorus concentration is controlled. A phosphor glass film can be formed on the sample surface. According to this method, a reaction on the order of seconds is used, so that the reaction temperature can be easily increased. Immediately after the reaction, a high-temperature (900 ° C. or higher) heat treatment is performed in the reaction vessel for several tens of seconds, so that the reaction can be performed with high density It is possible to form a thin film.

Furthermore, when a polycrystalline silicon film is formed on the surface of a silicon substrate, a single-wafer processing apparatus capable of performing a reaction by a rapid heating and quenching method using a small-volume reaction vessel is as follows:
Since the sample can be moved into and out of the reaction vessel at room temperature, the surface of the silicon substrate is not oxidized, and the interface between the polycrystalline silicon film and the silicon substrate can be kept clean. Also, by placing a sample in the above reaction vessel and performing a heat treatment with a chlorine-based gas or a fluorine-based gas introduced just before forming a polycrystalline silicon film, natural oxidation of the surface of the silicon substrate formed at room temperature is performed. Since the film can be removed, it is possible to obtain a cleaner interface. The reason why a large number of clean polycrystalline silicon films / silicon substrate surfaces are required is to eliminate impurity diffusion barriers and electrical barriers between the polycrystalline silicon film and the silicon substrate and to obtain good contact. In the present invention, a single-wafer forming apparatus having a configuration as shown in FIG. This forming apparatus is roughly divided into a heating source 3 necessary for heating only the reaction vessel 1 and the sample 2.
A gas line section comprising a reaction gas source 4, a reaction gas controller 5, and a gas exhaust unit 6, and
The control unit 7 of the heating source 3 and the reaction gas controller 5
It consists of. In addition, a transport unit necessary for taking the sample 2 in and out of the reaction container 1 is also provided.

In this forming apparatus, the heating section is constituted so that the temperature of the sample 2 can be controlled on the order of seconds. Also,
The internal volume of the reaction vessel is reduced so that the atmosphere in the reaction vessel can be replaced with various atmospheres in a short time. Further, in the reaction gas controller 5, mixing of different gases,
A gas generating closed bubbler for switching the gas flowing into the reaction vessel 1 and for introducing a steam atmosphere into the reaction vessel 1 is provided.

[0016]

【Example】

<Embodiment 1> An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 2, a single wafer type thin film forming apparatus was manufactured. Reaction vessel 9 for forming a thin film on the surface of sample 8
Is a quartz container having a content of 0.3 l,
Has a purge gas introducing cylinder 10 and a reaction gas introducing cylinder 1
1, and a reaction gas exhaust tube 12 were provided. The heating of the sample 8 is performed by a tungsten and halogen lamp 13, and the preliminary heating of the sample 8 (heating temperature; 100 to 300 ° C.)
The lamp 14 is also provided in the lamp house 15. The lamp house 15 includes a gas inlet tube 16 and a gas exhaust tube 17 capable of forcibly air-cooling the reactor 9 and a lamp house 15 for maintaining the inside of the reaction vessel 9 at a vacuum.
Was provided. In order to make the degree of vacuum in the reaction vessel 9 and the vacuum in the lamp house 15 the same, an evacuation controller 19 was provided. This evacuation controller 19
Is constituted by a control valve in addition to the vacuum exhaust pump, and can control the degree of vacuum in a range of 10 to 0.001 Torr.
The inner surface of the lamp house 15 was coated with a reflection coating by gold plating. Further, the temperature of the sample 8 is monitored using a pyrometer 20, and the input to the lamp 13 is controlled to be maintained at a predetermined temperature. Further, a door 22 having a purge gas exhaust pipe 21 is provided so that the sample 8 can be transported into the reaction container 9. The reaction gas is introduced into the reaction vessel 9 by the flow meters 24 to 24 of the gas flow controller 23.
After the gas is introduced from 32 into the reaction gas control unit 34 via the gas pipe 33, the required gas is supplied to the reaction gas introduction cylinder 11 connected to the reaction vessel 9. The gas control unit 3
In 4, a plurality of gas species whose flow rates are controlled can be allocated to 100 reaction gas introduction cylinders 11 provided in the reaction vessel 9 so that a thin film can be uniformly formed on the surface of the sample 8. The reason why 100 reaction gas introduction cylinders 11 are provided is that the reaction gas is more uniformly introduced onto the surface of the sample 8 to cause a more uniform reaction and to form a uniform film. Further, a bubbler 36 containing ultrapure water 35 was provided in order to create a steam atmosphere. The heating of the bubbler 36 is performed by a heater 37, and oxygen gas for water vapor carrier is controlled by the flow meter 25 and introduced into the bubble 36.
Steam is introduced into the reaction vessel 9 under the control of 39.

Hereinafter, an example of forming a thin film using the single wafer type thin film forming apparatus shown in FIG. 2 will be described.

(1) Formation of Thermal Oxide Film on Silicon Substrate Surface The oxidizing gas flow rate was set to 5 l / min by a flow meter 25, and the door 22 was introduced into the reaction vessel 9 through the purge gas introducing cylinder 10 while the oxidizing gas was introduced. Open, n-type, (100), 10
The Ωcm silicon substrate 8 was transported and inserted into the reaction vessel 9. At this time, the temperature inside the reaction vessel 9 is 100 ° C. or less. Thereafter, the door 22 is closed, purging is performed for 30 seconds, and the gas flow rate is set to 1 l / min.
3, the silicon substrate 8 was heated to 1100 ° C.
At this time, the temperature of the silicon substrate 8 reached 1100 ° C. in about 5 seconds. After performing thermal oxidation with a heating time of 60 seconds, the oxygen gas flow rate was set to 5 l / min, and
Silicon substrate 8 cooled to 0 ° C. or less and thermally oxidized
Was taken out of the reaction vessel. As described above, when purging (preliminary heating described in (2)), heating, and cooling are performed in the same container, the throughput of sample processing is reduced.
Therefore, from the viewpoint of throughput, a forming apparatus including a purge unit, a heating unit, and a cooling unit is advantageous. The problem of throughput can be improved by using the reaction vessel described here as a reaction vessel of a heating section and further adding a purge (preheating) section and a cooling section. The formed silicon oxide film has a thickness of 10 nm, and has a withstand voltage of about 10 nm as compared with a silicon oxide film of the same thickness formed by thermal oxidation (oxidization at 900 ° C. for 30 minutes) using an ordinary electric furnace. 5%
As a result, the surface charge of the oxide film / silicon substrate could be reduced to about half. As described above, if thermal oxidation is performed at a high temperature for a short time, a higher quality silicon oxide film can be formed as compared with normal thermal oxidation.

(2) Formation of Oxide Film by Steam Oxidation of Silicon Substrate (When Bubbler 36 is Used) In the same manner as in the above method (1), the silicon substrate 8 is purged with oxygen gas controlled at 5 l / min. To the reaction vessel 9
, The door 22 was closed, and a purge was performed for 30 seconds.
After that, the silicon substrate 8 was kept at 150 ° C. by the preheating lamp 14 at an oxygen gas flow rate of 1 l / min, and preheating was performed for 5 seconds. Then, the three-way valves 38 and 39 are controlled to supply oxygen gas to the bubbler 36 whose water temperature is maintained at 95 ° C.
, The generated steam was introduced into the reaction vessel 9 from the purge gas introduction cylinder 10. 30 seconds after the introduction of steam into the reaction vessel 9, the silicon substrate 8 was heated to 1100 ° C. by the lamp 13 to perform thermal oxidation for 60 seconds.
Here, the reason that the sample temperature is kept at 100 ° C. or higher when introducing steam into the reaction vessel is to prevent contamination due to condensation of steam on the sample surface. After this,
When the three-way valves 38 and 39 are controlled so that oxygen gas is directly introduced into the reaction vessel 9, the flow rate of oxygen gas is set to 5 l / min, and when the temperature of the silicon substrate 8 reaches 200 ° C., the silicon substrate 8 was removed from the reaction vessel. The thickness of the thermal oxide film on the substrate 8 thus formed is 50
nm. Here, as a result of comparing the presence or absence of preheating,
With preheating, a clean oxide film was formed. As described above, high-temperature, short-time oxidation using a steam atmosphere can be performed by performing preheating and providing the bubbler 36.

(3) Formation of Oxide Film by Steam Oxidation of Silicon Substrate (When Hydrogen Combustion Method is Used) After purging, the oxygen gas is controlled at 1 l / min. The substrate 8 was heated to 900 ° C. When the temperature of the silicon substrate 8 reaches 900 ° C., the flow rate of the hydrogen gas is controlled to 1 l / min by the flow meter 26, and the reaction gas control unit 34 is controlled.
Then, hydrogen gas was introduced through the reaction gas introduction cylinder 11 of the entire reaction vessel 9. At this time, in the reaction vessel 9,
Water vapor is generated by the reaction between hydrogen and oxygen. Reaction vessel 9
10 seconds after the introduction of the hydrogen gas into the silicon substrate, the temperature of the silicon substrate 8 is set to 1100 ° C., steam oxidation is performed for 60 seconds, the introduction of the hydrogen gas is stopped, and the heating of the silicon substrate 8 at 1100 ° C. is stopped. did. The nitrogen gas flow was directly controlled at 5 l / min by the meter 25, and nitrogen purge was performed through the reaction gas control unit 34 and the reaction gas introduction cylinder 11. At this time, the exhaust of nitrogen and oxygen gas was performed not only by the exhaust pipe provided on the door 22 but also by the reaction gas exhaust pipe 12 of the reaction vessel 9. While performing the purging, when the temperature of the silicon substrate 8 became 200 ° C. or lower, the steam-oxidized substrate 8 was taken out of the reaction vessel 9. At this time, the obtained oxide film thickness was 40 nm. Thus, steam oxidation is possible by the hydrogen combustion method without preheating.

(4) Formation of Thermal Oxide Film on Polycrystalline Silicon Film Surface The silicon substrate surface forms a silicon oxide film having a thickness of 20 nm, and phosphorus is introduced at a concentration of 1 × 10 ²¹ / cm ^3. Sample 8 on which a crystalline silicon film (thickness = 3000 nm) was formed was processed. The treatment method was the same as in the above (1), and the oxidation conditions were 1100 ° C. and 60 seconds. The thickness of the silicon oxide film on the surface of the polycrystalline silicon film obtained at this time was 20 nm. The withstand voltage of this silicon oxide film was about 10 MV / cm, and the withstand voltage increased about twice as compared with the silicon oxide film formed by thermal oxidation (900 ° C., 30 minutes) using a normal electric furnace. in this way,
According to the high-temperature and short-time thermal oxidation, a high-quality silicon oxide film can be formed even by oxidizing the surface of the polycrystalline silicon film.

(5) Formation of polycrystalline silicon film Reaction vessel 9 A silicon substrate 8 having a silicon oxide film patterned in a nitrogen purged state (5 l / min) is placed in a reaction vessel 9
After closing the door 15, the evacuation control unit 19
Was operated to stop the nitrogen purge, and the inside of the reaction vessel 9 and the lamp house 15 was evacuated to 1 × 10 ⁻⁶ Torr.
Next, the flow rate of the hydrogen chloride gas was set to 1 cc /
After introducing hydrogen chloride gas into the reaction vessel 9 through the reaction gas control section 34 and the reaction gas introduction cylinder 11, the silicon substrate 8 is heated to 1100 ° C.
A second surface treatment was performed.

When the hydrogen chloride gas and the first monosilane gas described below are introduced into the reaction vessel 9, the degree of vacuum in the reaction vessel 9 and the lamp house 15 is made the same.
In order to prevent the backflow of hydrogen chloride gas and the following monosilane gas into the lamp house, the cooling gas introduction cylinder 16 is used.
Was introduced with nitrogen gas. After the surface treatment, the temperature of the sample 8 was maintained at 650 ° C., the flow rate of the monosilane gas was controlled to 1 cc / min by the flow meter 27, and the monosilane gas was introduced into the reaction vessel 9 through the control section 34 of the reaction gas and the introduction cylinder 11. . Immediately after the introduction of the monosilane gas, the degree of vacuum in the reaction vessel 9 was controlled to 1 Torr by the vacuum evacuation controller 19, and the monosilane gas was decomposed for 60 seconds.

Thereafter, the supply of the monosilane gas is stopped,
The heating of Sample 8 was stopped. Next, a nitrogen gas is introduced as a purge gas from the reaction gas introducing cylinder 11, and after the degree of vacuum in the reaction vessel 9 is gradually returned to the atmospheric pressure, the nitrogen purge (5 l / min) is switched from the purge introducing cylinder to the introduction. When the temperature of the sample 8 becomes 200 ° C. or less, the sample 8
Was taken out of the reaction vessel 9. The thickness of the polycrystalline silicon film obtained at this time was 30 nm. In addition, by performing the above-described surface treatment, there is no natural oxide film serving as a barrier against conductivity or impurity diffusion at an interface between the polycrystalline silicon film formed on the portion where the silicon substrate surface is exposed and the silicon substrate, A clean polycrystalline silicon film / silicon substrate interface could be obtained.

(6) Formation of Silicon Nitride Film As in (5) above, after evacuating to 1 × 10 ⁻⁶ Torr, the flow rate of the nitrogen gas is controlled to 1 cc / min by the flow meter 24 and While being introduced into the reaction vessel 9 from the reaction vessel 11, the operation of the vacuum
The degree of vacuum inside the lamp house 15 was maintained at 1 Torr. Thereafter, the silicon substrate 8 is heated by heating the lamp 13.
The temperature was set to 800 ° C., and the flow rates of ammonia gas and dichlorosilane gas were controlled to 2 cc / min and 0.5 cc / min by flow meters 28 and 31, respectively. still,
At this time, the degree of vacuum in the reaction vessel 9 and the lamp house 15 is kept at 1 Torr. After the introduction of the above-mentioned amminia and dichlorosilane gas, the reaction was carried out for 60 seconds, only the two kinds of reaction gases were stopped, and the inside of the reaction vessel 9 was replaced with nitrogen gas for 10 seconds while keeping the inside of the reaction vessel 9 at 1 Torr. went. Thereafter, the heating of the silicon substrate 8 was stopped, the degree of vacuum in the reaction vessel 9 was gradually reduced to atmospheric pressure, and nitrogen gas (5 l / min) was introduced from the purge gas introduction cylinder 10 to remove silicon. When the temperature of the substrate 8 became 200 ° C. or less, the silicon substrate 8 was taken out of the reaction vessel. The silicon nitride film formed at this time has a thickness of 20 nm,
It has the same oxidation resistance as that obtained by a normal CVD method.

(7) Formation of Phosphorus Glass Film After the silicon substrate 8 is inserted while the inside of the reaction vessel 9 is purged with nitrogen gas (5 l / min) introduced from the purge gas introduction cylinder 10, the door 22 is closed. After a lapse of 30 seconds, the flow rate of the nitrogen gas was changed to 1 l / min, and the introduction of the nitrogen gas was switched from the purge gas introduction cylinder 10 to the reaction gas introduction cylinder 11. Thereafter, the silicon substrate 8 was heated to 600 ° C., and dry air was introduced from the cooling gas introduction cylinder 16 to forcibly cool the reaction vessel 9. At this time, the wet dry air was exhausted from the cooling gas exhaust pipe 17. Ten seconds after heating the silicon substrate 8 to 600 ° C., the flow rates of oxygen gas, monosilane gas and phosphine gas were adjusted to 0.2 l / min, 10 cc / min and 0.4 by flow meters 25.27 and 29, respectively.
At a rate of cc / min, these reaction gases were introduced into the reaction vessel 9 from the reaction gas introduction cylinder 11. Here, each one reaction gas introducing cylinder 11 uses one kind of reaction gas alone, and reacts these reaction gases only in the vicinity of the surface of the silicon substrate 8 in the reaction vessel 9. I have.
After this reaction was performed for 60 seconds, the supply of the reaction gas except for the nitrogen gas was stopped, and after 10 seconds, the silicon substrate 8 was removed for 100 seconds.
Heating was performed to 0 ° C., and annealing was performed for 20 seconds. After this,
The heating of the silicon substrate 8 was stopped at a nitrogen gas flow rate of 5 l / min. When the temperature of the silicon substrate 8 became 200 ° C. or less, the introduction of the nitrogen gas was switched from the reaction gas introduction cylinder 11 to the purge gas introduction cylinder 10, and then the silicon substrate 8 was taken out of the reaction vessel. The phosphorus glass thus formed has a phosphorus molar concentration of 4% and a film thickness of 100 n.
m. The etching rate in an etching solution having a composition of HF / H ₂ O = 1/10 is about 100 nm.
/ Min. This etching rate was about one-tenth or less of that of a phosphorus glass film having the same molar concentration obtained by a normal CVD method. The etching rate after phosphorus glass formed by a normal CVD method or after densification at 1000 ° C. for 30 minutes was almost the same. Therefore,
According to the above method, there is no need to further perform annealing for densification of the phosphorus glass. Thus, in this method, a phosphorus glass film can be formed and densified in the same reaction vessel 9, so that a high-quality phosphorus glass film can be easily formed. When the surface of the silicon substrate 8 has irregularities, when formed by this method, compared with a conventional low-temperature CVD method of about 450 ° C.,
The step coverage at the step was good. That is, the thickness of the step portion of 0.5 μm is 40% or less of the thickness of the flat portion in the usual method, but is 90% or more according to the present invention.

(8) Formation of Boron Phosphorus Glass Film The silicon substrate 8 is inserted while the inside of the reaction vessel 9 is purged with nitrogen gas (flow rate = 5 l / min), and
After 30 seconds had passed, the nitrogen gas flow rate was changed to 1 l / min after 30 seconds had elapsed, and the introduction of the nitrogen gas was switched from the purge gas introduction cylinder 10 to the reaction gas introduction cylinder 11. Thereafter, the silicon substrate 8 was heated to 450 ° C., and the reaction vessel 9 was forcibly air-cooled as described in (7) above. 10 seconds after the silicon substrate 8 was heated to 450 ° C., the flow rates of oxygen gas, monosilane gas, phosphine gas, and diborane gas were changed by flow meters 25, 27, 29, and 30 to 0.2 / min, 10 cc / min, respectively. 0.4cc / and
The reaction gas was introduced into the reaction vessel 9 from the reaction gas introduction cylinder 11 at a rate of 0.3 cc / min. The reaction of these reaction gases is performed only on the surface of the silicon substrate 8. After performing this reaction for 60 seconds, supply of all the reaction gases except for the nitrogen gas was stopped, and after 10 seconds, the silicon substrate 8 was removed.
Annealing was performed for 20 seconds by heating to 1000 ° C. Thereafter, the heating of the silicon substrate 8 was stopped at a nitrogen gas flow rate of 5 l / min. When the temperature of the silicon substrate 8 became 200 ° C. or lower, the nitrogen gas introduction was switched from the reaction gas introduction cylinder 11 to the purge gas introduction cylinder 10, and then the silicon substrate 8 was taken out of the reaction vessel. The obtained boron phosphorus glass had a molar concentration of boron and phosphorus of 3 mol% and 4 mol%, respectively, and a film thickness of 120 nm. The boron phosphorus glass obtained in this manner is a high-quality film that has been densified. At this time, when the surface of the silicon substrate 8 has irregularities, when boron phosphorus glass is formed by such a method, the glass is reflowed by the 1100 ° C. annealing, and the surface of the glass film is flattened.

As described above, according to the present invention, a thin film can be formed in a short time and at a high temperature in the same manner as in a normal thin film forming method, and thus, as described in the above (1) to (8), A thin film of good quality can be formed as compared with the method. In addition, since the controllability of time control and atmosphere control is good, different kinds of thin films can be simultaneously formed in the same container.

<Embodiment 2> An EP was formed by using the above-mentioned thin film forming method.
An embodiment in which a ROM is manufactured will be described with reference to FIG.

Plane orientation; (100), conductivity type; p-type;
After forming a silicon oxide film 41 having a thickness of 10 nm on the silicon substrate 40 having a resistivity of 10 Ωcm by the method (1) (temperature = 1100 ° C .; time = 60 seconds), the inside of the reaction vessel 9 and the lamp house are formed. The inside of 15 was evacuated by 1 × 10 ⁻⁶ Torr. Thereafter, a reaction is performed at a substrate temperature of 800 ° C. for 300 seconds by the same method as in the above (6), and a silicon nitride film 42 having a thickness of 100 nm is formed.
Was formed. Thereafter, normal purging and cooling are performed, the substrate 40 is taken out of the reaction vessel 9, and the resist film 43 and the silicon oxide film are formed using a normal photo process.
41 and the silicon nitride film 42 were processed. Then, boron ions 44 were implanted at a rate of 5 × 10 ⁻¹² / cm ² at an acceleration energy of 60 keV to form an implanted layer 45, and then the resist film 43 was removed (a). Next, a silicon oxide film 46 having a thickness of 0.5 μm was formed by the method described in the above (2) (temperature = 1200 ° C., time = 300 seconds, bubbler temperature = 95 ° C.). At this time, the p-type field diffusion layer 47 was formed under the silicon oxide film 46 by electrically activating boron in the implanted layer 45 (FIG. 4B).

Next, after removing the silicon nitride film 42 and the silicon oxide film 41, the silicon oxide film having a thickness of 20 nm is formed by the method described in the above (1) (temperature = 1150 ° C., time = 120 seconds). (Gate oxide film) 48 was formed. Thereafter, for controlling the threshold value, boron ions 49 were implanted at an acceleration energy of 60 keV by 2.5 × 10 ⁻¹¹ / cm ² to form a boron implanted layer 50 (c).

Next, as shown in the above (5), the sample is inserted into the reaction vessel 9 and the reaction vessel 9 and the lamp house are inserted.
15 After evacuating the inside to 1 × 10 ^-6 Torr,
Heated to 650 ° C. Immediately after the sample temperature reached 650 ° C., the degree of vacuum in the reaction vessel 9 was maintained at 1 Torr, and the flow rates of monosila gas and phosphine gas were controlled to 1 cc / min and 0.01 cc / min by flow meters 27 and 29, respectively. The above gas was introduced into the reaction vessel 9 from the reaction gas introduction cylinder 11, and the reaction was performed for 420 seconds. Thereafter, the supply of the reaction gas and the heating of the sample were stopped, and the pressure in the reaction vessel 9 was increased to atmospheric pressure, purging and cooling were performed as described in (5) above, and when the sample temperature became 200 ° C. or less. The sample was taken out of the reaction vessel. At this time, the formed polycrystalline silicon film 51
The film thickness was 210 nm, and the layer resistance was about 25 Ω / port. At this time, the boron implanted layer 50 was activated. The polycrystalline broken silicon film 51 was processed using a subsequent photo process (d).

Next, the method shown in the above (3) (temperature = 10
(E.g., 50 ° C., time = 120 seconds) to form a silicon oxide film 52 having a thickness of 20 nm (e).
A polycrystalline silicon film 53 having the same specifications as that of the polycrystalline silicon film 53 is deposited (f), and then the polycrystalline silicon film 53, the silicon oxide film 52, and the polycrystalline silicon film 51 are processed by a normal photo process ( g). At this time, in the two types of polycrystalline silicon films, the upper part becomes the control gate electrode 42 and the lower part becomes the floating gate electrode 40.

Next, the method (3) (temperature = 1050 ° C.,
Time = 120 seconds), the silicon oxide film 54 having a thickness of 20 nm
Then, arsenic ions 55 were implanted at an acceleration energy of 100 keV by 1 × 10 ¹⁶ / cm ² to form an arsenic implanted layer 56 serving as a source and a drain (h).

Thereafter, the phosphorus glass films 57 and 5 having a phosphorus concentration of 0.5 mol% and 4 mol% are obtained by the method (7).
8 were each formed with a thickness of 0.3 μm. The phosphorus glass forming conditions are as follows. The lower phosphorus glass film 57 was formed by reacting the monosilane gas and the phosphine gas at flow rates of 10 cc / min and 0.05 cc / min at 600 ° C. for 120 seconds. The upper phosphorus glass film 58 has a flow rate of the monosilane gas and the phosphine gas of 10 cc /
And 0.4 cc / min at 600 ° C. for 120 seconds.

The flow rate of oxygen gas was 0.2 l / min. Then, a boron-phosphorus glass film 59 having a thickness of 0.6 μm is formed by reacting for 300 seconds under the same conditions as in the above (8) by the method of the above (8). Immediately after that, a nitrogen atmosphere (flow rate = 1) is formed.
(l / min), annealing at 1050 ° C for 10 seconds,
As described above, a boron-phosphorus glass film 60 whose surface was flattened by reflow was formed. By the annealing treatment, the arsenic implanted layer 56 was electrically activated, and the phosphorus glass films 57 and 58 were densified (i).

Next, the boron-phosphorus glass film 60, the phosphorous glass films 58 and 57, and
After processing the silicon oxide film 48 and forming a contact hole, annealing is performed at 1050 ° C. for 10 seconds, and as shown in FIG. Relaxed (j).

Finally, after the aluminum electrode 62 is manufactured by the ordinary process, the aluminum electrode
Hydrogen annealing at 20 ° C for 20 seconds was performed to produce an EPPON device.

According to the present embodiment, the thin film forming process can be reduced from 9 steps to 6 steps as compared with the normal process, and the annealing treatment for densifying and reflowing the above several kinds of glass films is performed by thin film forming. Immediately after that, the treatment can be performed in the same container within a short time, so that the annealing treatment can be substantially reduced from three times to two times, and the process is simplified. In addition, since the control of the reaction time is on the order of seconds, the controllability of the thin film forming process is improved, and various annealings can be performed in a minimum necessary time, and unnecessary heat treatments (for example, source and drain regions) are performed. , Which causes an increase in the junction depth and makes it difficult to form the source and drain), thereby improving the controllability of the annealing process.

Further, according to the present embodiment, as shown in FIG. 3 (i), the surface is flattened by the reflow treatment, and the accuracy of the photolithography process for forming contact holes can be improved. As shown in FIG. 9J, the contact holes could be made oblique and gentle, so that the disconnection was prevented in the formation of the electrodes 62.

According to this embodiment, the gate insulating film 48
Of the insulating film 52 between the floating gate 51 and the control gate 53 can be improved by about 2.5 times. As a result, the reliability of the device can be improved.

[0043]

According to the present invention, a film can be formed without damaging the reaction vessel. In addition, different types of thin films can be formed in the same reaction vessel, and annealing can be performed immediately after the thin film is formed. In addition, since the reaction can be controlled on the order of seconds, there is an effect of improving process controllability. Further, since the reaction temperature can be increased, it is effective in forming a thin film having good characteristics.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an example of a single-wafer insulating film forming apparatus according to the present invention.

FIG. 2 is a schematic diagram of the forming apparatus.

FIG. 3 is an EPROM manufacturing process diagram using the method of the present invention.

[Explanation of symbols]

1, 9: reaction vessel, 2, 8: sample substrate, 3, 13, 14
... heating lamp, 4 ... reaction gas source, 5, 34 ... reaction gas control unit, 6 ... gas exhaust unit, 7 ... control unit, 10 ... purge gas introduction cylinder, 11 ... reaction gas introduction cylinder, 12 ... reaction gas exhaust cylinder , 15 ... lamp house, 16 ... cooling gas introduction cylinder, 17
... Cooling gas exhaust tube, 18 ... Vacuum exhaust tube, 19 ... Vacuum exhaust control unit, 20 ... Pyrometer, 21 ... Purge gas exhaust tube, 22 ... Door, 23 ... Reactive gas flow control unit, 24-3
2 ... flow meter, 33 ... gas pipe, 35 ... ultrapure water, 36 ... bubbler, 37 ... heater, 38, 39 ... three-way valve, 40 ...
p-type silicon substrate, 41, 46, 48, 52, 54 ... silicon thermal oxide film, 42 ... silicon nitride film, 43 ... resist film, 44, 49 ... boron ion, 45, 50 ... boron implanted layer, 47, 50 ... p-type diffusion layers, 51, 53... n +
Type polycrystalline silicon film, 55: arsenic ion, 56: arsenic implanted layer or n + type diffusion layer, 57, 58: phosphorus glass film, 59 to 61: boron phosphorus glass film, 62: aluminum electrode.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasuo Wada 1-280 Higashi Koikebo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (56) References JP-A-61-6199 (JP, A) JP-A-54 -21266 (JP, A) JP-A-61-271820 (JP, A)

Claims (5)

(57) [Claims] 1. A step of inserting a sample into a thermal reaction vessel surrounded by a lamp house, a step of applying substantially the same degree of vacuum to the interior of the lamp house and the interior of the thermal reaction vessel, and Controlling the temperature of the sample to a first predetermined temperature, forming a first film on the surface of the sample in a first atmosphere, and controlling the temperature of the sample to a second temperature on the order of seconds. And a step of treating the sample in a second atmosphere different from the first atmosphere. 2. The method according to claim 1, wherein said first atmosphere is composed of a plurality of types of reaction gases, and said first atmosphere is introduced from a plurality of reaction gas inlets. A single-wafer-type thin-film forming method, wherein each of the reaction gas inlets introduces one of the plurality of reaction gases. 3. A thermal reaction vessel, a lamp house provided so as to surround the thermal reaction vessel, a single-wafer sample table provided in the thermal reaction vessel, and a lamp house provided in the lamp house. A lamp for heating the temperature of the sample on the sample stage in the order of seconds, a reaction gas control unit, a reaction gas inlet provided in the thermal reaction vessel, a reaction gas exhaust means, the inside of the thermal reaction vessel, Means for making the inside of the lamp house substantially the same degree of vacuum. 4. A single-wafer thin film forming apparatus according to claim 3, wherein said plurality of reaction gas inlets are means for introducing a plurality of types of reaction gas, and each of said plurality of reaction gas inlets is one type. A single-wafer type thin film forming apparatus, characterized in that it is means for introducing a reactive gas. 5. A single-wafer thin film forming apparatus according to claim 3, wherein said thermal reaction vessel has a purge gas inlet and said purge gas inlet.
A single-wafer type thin film forming apparatus comprising: a reaction gas inlet provided separately from a digas inlet.