JPH0786263A - Heat treatment method - Google Patents

Abstract

(57) [Abstract] [Purpose] Even if the aspect ratio is high, the film can be formed uniformly and the surface of the object to be processed can be flattened without generating voids. Provided is a heat treatment method for forming a coating film having excellent properties and mechanical properties on an object to be processed. According to the present heat treatment method, a predetermined reactive gas is supplied into the reaction vessel 30 heated by an external heater (resistance heating element 21) and heated to 600 ° C., and the heat treatment port 40 is used in the reaction vessel 30. After the reaction product of the reactive gas is deposited on the 25 semiconductor wafers W thus held to form the BPSG film 1, the reactive gas is replaced with an inert gas and the inside of the reaction vessel is set to 900 by the resistance heating element 21. After the BPSG film 1 is heated to 0 ° C. to melt and flatten it, the inside of the reaction vessel 30 is cooled to 600 ° C., and the film forming step, the flattening step and the cooling step are continuously performed at least once.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat treatment method.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor device manufacturing process, a silicon film such as a polysilicon film or an amorphous silicon film, a silicon oxide film such as a PSG film or a BPSG film, or a film such as a silicon nitride film is subjected to a low pressure CVD or a normal process. It is widely practiced to form a film on an object to be processed such as a semiconductor wafer by a process such as pressure CVD.

In the film forming process of such a silicon coating film, for example, batch processing of semiconductor wafers is widely performed by a heat treatment apparatus or the like. When a film is formed by heat treatment using, for example, a low pressure CVD apparatus as a heat treatment apparatus, a large number of objects to be treated such as semiconductor wafers are made of ceramics such as quartz in a reaction container kept at a predetermined heat treatment temperature. It is stored via a heat treatment boat, and TEOS, phosphine (PH3), TM are placed in the reaction vessel under reduced pressure.
B and B by introducing a reactive gas such as oxygen
The interlayer insulating film such as the PSG film is formed by one operation. After the film formation, the object to be processed is taken out from the reaction container via the heat treatment boat to accommodate the next object to be processed. During this time, the reaction container is heated to the heat treatment temperature.

On the other hand, in recent years, semiconductor devices have become highly integrated, their wiring structures have become finer and multilayered, and their aspect ratios have become higher, resulting in significant step differences in each wiring layer. It has become an important issue to improve the step coverage in the upper layer of the wiring layer by flattening the step by a reflow technique or the like.

[0005]

However, in the conventional heat treatment method, when the aspect ratio of the wiring of the semiconductor device is 1 or less, the reactive gas easily reaches the sidewalls and bottoms of the trenches between the wiring layers and is relatively uniform. It is possible to perform a simple film-forming operation once, and to fill the groove between the wiring layers by subsequent reflow without generating voids due to melting of the film, but as described above, the semiconductor device is highly integrated. When the aspect ratio exceeds 1 and the groove between the wiring layers becomes deep, it becomes difficult for the reactive gas to reach the inside of the groove, and the film 1 is formed at the time of film formation as shown in FIG. When overhanging between 2 and 2 and reflowing in that state as in the conventional case, a void 3 exaggerated in FIG. 1B is formed between the wiring layers 2 and 2, and the electrical characteristics and mechanical properties of the film 1 are increased. The strength may deteriorate and There is a problem that such generates a planar defects due to voids.

Further, in the conventional heat treatment method, since the object to be processed is unloaded from the reaction vessel after the film formation and then the reflow treatment is separately performed, the object to be processed is exposed to the air during the unloading and the surface thereof is exposed. There is a problem that a natural oxide film may be formed or other impurities may be mixed in, and the film may be deteriorated.

The present invention has been made in order to solve the above-mentioned problems, and even if the aspect ratio is high, a uniform film can be formed to flatten the surface of the object to be processed without generating voids. Moreover, it is an object of the present invention to provide a heat treatment method capable of forming a coating film having excellent electrical properties and mechanical properties on an object to be processed without mixing impurities.

[0008]

According to a first aspect of the present invention, there is provided a heat treatment method in which a predetermined reactive gas is supplied into a reaction vessel heated by an external heater to a predetermined reaction temperature. After depositing a reaction product of a reactive gas on a plurality of objects to be processed held by a holder in the reaction container to form a film, the reactive gas is replaced with an inert gas and the external heater is used. After heating the inside of the reaction vessel to a predetermined temperature to melt and flatten the coating, cool the inside of the reaction vessel to the reaction temperature, and further continuously, at least the coating forming step, the flattening step and the cooling step. It was done once.

The heat treatment method according to claim 2 of the present invention is the method according to claim 1, wherein the inside of the reaction vessel is heated at a temperature rising rate of 50 to 200 ° C./min. The inside is cooled at a temperature decreasing rate of 30 to 100 ° C./min.

The heat treatment method according to claim 3 of the present invention is the method according to claim 1 or 2,
As the external heater, molybdenum disilicide is used to heat the inside, and an air flow is created on the outer peripheral surface of the reaction vessel to cool the inside.

The heat treatment method according to claim 4 of the present invention is the method according to any one of claims 1 to 3, wherein the peripheral portion of the object is supported by a support member having a large heat capacity. The object to be processed is heated and cooled through the support member.

[0012]

According to the first aspect of the present invention, the reaction vessel is heated by the external heater to raise the inside temperature to a predetermined reaction temperature, and then a predetermined reactive gas is supplied into the reaction vessel. Then, the reactive gas reacts on the surfaces of the plurality of objects to be processed held by the holder in the reaction container, the reaction products are deposited on the objects to be processed to form a film, and then the reactive gas is not absorbed. After replacing with active gas, the inside of the reaction vessel is heated by an external heater and the inside is heated to a predetermined temperature (melting temperature of the coating).
When heated to, the coating melts and the melt flows by its own weight to flatten the surface of the object to be treated, and in that state the molten coating solidifies when the reaction vessel is cooled to the reaction temperature of the reactive gas, After that, the same film forming step, flattening step and cooling step are successively performed at least once, and at least two film forming operations are continuously performed in the same reaction vessel to suppress the overhang of the film. Uniform film formation, and even if the aspect ratio of the object to be processed is high, it can be planarized without generating voids, and since the object to be processed is not unloaded to the outside,
It is possible to form a film without mixing impurities such as oxygen into the film.

Further, according to the invention of claim 2 of the present invention, in the invention of claim 1, 5
The reflow process can be performed in a short time by raising the temperature at 0 to 200 ° C./minute, and the inside of the reaction vessel is 30 to 100 ° C./minute.
The heat treatment can be performed in a short time by cooling in minutes and shortening the time until the next film formation.

According to the invention of claim 3 of the present invention, in the invention of claim 1 or 2,
Using an external heater made of molybdenum disilicide, it is possible to obtain a high calorific value and raise the temperature in the reaction vessel in a short time.
In addition, it is possible to cool in a short time by creating an air flow on the outer peripheral surface of the reaction container and forcibly cooling the inside of the reaction container.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the peripheral portion of the object to be processed is supported by a supporting member having a large heat capacity. Since the object to be processed is heated and cooled through this support member, the entire object to be processed can be uniformly heat-treated even with rapid heating and cooling.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in FIGS. First, a low pressure CVD apparatus preferably used in this embodiment will be described with reference to FIGS. 1 and 2. This low pressure CVD apparatus, as shown in FIG.
0 and a heating furnace 20 which is vertically disposed in the heating furnace 20 and has a double-wall structure for heat treatment (hereinafter, referred to as "reaction 30), and the reaction vessel 30 loaded in the reaction vessel 30 to seal the reaction vessel 30 and subject, for example, about 30 objects W (hereinafter, represented by “semiconductor wafer”) W to heat treatment. Holder (hereinafter referred to as "heat treatment boat") 4
0, and a cooling device 50 for forcibly cooling the semiconductor wafer W held by the heat treatment boat 40 from the outside of the reaction container 30.
And is configured. When the semiconductor wafer W is heat-treated, the heat treatment boat 40 is moved up and down in the direction of arrow A through a not-shown elevating mechanism to be loaded into the reaction container 30, and after the semiconductor wafer W is heat-treated, it is unloaded from the reaction container 30. Is configured to.

The heating furnace 20 is formed as a cylindrical body having a closed upper end and an opened lower end. That is, as shown in FIG. 1, the heating furnace 20 includes an external heater (for example, a coil-shaped resistance heating element 21) that is attached to the inner surface of the straight body portion of the tubular body and is made of, for example, molybdenum disilicide.
A heat insulating material 22 that holds the resistance heating element 21 and covers the entire inner surface of the straight body portion and the upper end portion of the cylindrical body, and a shell made of stainless steel or the like that covers the entire outer surface of the heat insulating material 22 (not shown). The temperature inside the reaction vessel 30 is heated and controlled within a short time, for example, to a range of 500 to 1200 ° C. by the resistance heating element 21 made of molybdenum disilicide or the like, which has a large calorific value. On the other hand, a predetermined heat treatment is performed in a short time. In addition, the resistance heating element 21 made of, for example, molybdenum disilicide is used.
Is configured to be able to heat the inside of the reaction container 30 at a temperature rising rate of 50 to 200 ° C./min. Temperature rising rate is 50 ° C /
If it is less than minutes, unnecessary heat may be applied for a long time, which is not preferable, and if it exceeds 200 ° C./minute, the entire surface of the semiconductor wafer W cannot be uniformly heated via a ring-shaped support body 41 described later, There is a possibility that a temperature gradient may occur in the plane, which is not preferable. Further, the resistance heating element 21 made of molybdenum disilicide can obtain a large surface heating load of 20 W / cm ² at 1200 ° C., for example. Therefore, for example, even in the case of a thin wire having a diameter of 3.5 mm, the inside of the reaction vessel 30 can be heated at a temperature rising rate of 100 ° C./min. By using cooling together, the inside of the reaction vessel 30 can be cooled at a temperature lowering rate of 50 ° C./min.

Further, as shown in FIG. 1, the reaction vessel 30 has an outer cylinder 31 formed of a heat-resistant and corrosion-resistant material such as quartz having an upper end closed and a lower end opened, and the outer cylinder 31. An inner cylinder 32 which is inserted and arranged with the axes aligned with each other with a gap left between the upper and lower ends of the outer cylinder 31 by using the same heat-resistant and corrosion-resistant material as that of the outer cylinder 31 to uniformly heat all the semiconductor wafers W. It is configured as a double-walled structure container equipped with. Further, the reaction container 30 is configured with a manifold 33 made of a metal such as stainless steel at its lower end.

Further, the manifold 33 has an exhaust pipe 33B made of the same material as the main body 33A connected to an exhaust system such as a vacuum pump for exhausting the inside of the reaction vessel 30, and a position displaced from the exhaust pipe 33B in the circumferential direction. And a gas introduction pipe 33C made of a heat-resistant and corrosion-resistant material such as quartz, which is inserted from the side and bent upward along the inner peripheral surface of the inner cylinder 32 to introduce an inert gas such as nitrogen. ing. The gas introduction pipe 33C extends along the inner peripheral surface of the inner cylinder 32 along the entire length thereof, and a plurality of nozzles (not shown) are formed at equal intervals along the entire length to form a reaction container. The reactive gas can be uniformly supplied into the entire reaction container 30 toward the center of the reaction container 30. Then, during the heat treatment, reactive gases such as TEOS, PH3, TMB and oxygen are introduced from each gas introduction pipe 33C, and these gases are reacted on the surface of the semiconductor wafer W to form a coating film such as a BPSG film on the surface of the semiconductor wafer W. Is formed.

The heat treatment boat 40 is made of, for example, a material having excellent heat resistance and corrosion resistance, such as quartz.
A support member (ring-shaped support 41) (see FIG. 2) that individually supports 0 semiconductor wafers W one by one, and these ring-shaped supports 41 are supported in parallel at equal intervals in the vertical direction, A plurality of support rods 42 to be fixed, and these support rods 42
A heat insulating body 43 connected to the lower end of the heat insulating body, a magnetic seal shaft 43 connected to the center of the lower surface of the heat insulating body 42, and a magnetic seal unit 44 connected to the magnetic seal shaft 43.
It is configured to rotate via the magnetic fluid of the magnetic seal unit 44 while being inserted into the reaction container 30. It should be noted that the inner surface of the flange 45 is covered with ceramics 45A such as quartz so that particles are not generated from the flange 45 during heat treatment.

As shown in FIG. 2, the ring-shaped support body 41 has a support portion 41A having a flat surface for supporting the semiconductor wafer W at the peripheral portion, and a support rod 42 integrated with the support portion 41A. It is formed of a fixed portion 41B that is fixed. The distance between the upper and lower ring-shaped supports 41, 41 is set to, for example, 9.525 mm between the centers of the upper and lower semiconductor wafers W (thickness 0.7 mm) in the thickness direction. Further, the support portion 41A is formed so that the thickness gradually increases from the inner diameter to the outer side, and the heat capacity increases toward the outer periphery. Therefore, when the ring-shaped support 41 is not provided as in the conventional case, the radiant heat from the peripheral side surface of the reaction container 30 is shielded by the upper and lower semiconductor wafers W, the radiant heat does not enter the inside of the semiconductor wafer W, and the peripheral edge The temperature of the peripheral portion is higher than that of the inner side, and a temperature gradient is generated in the plane, and conversely, at the time of cooling, the upper and lower semiconductor wafers W adjacent to each other cause the inside of the semiconductor wafer W to be cooled. The heat dissipation is hindered, the heat dissipation from the peripheral portion is promoted, a temperature gradient is also generated in the surface, and the semiconductor wafer W is slipped or warped. However, when the ring-shaped support body 41 is provided, the ring-shaped support body 41 is gradually heated during heating to suppress a rapid temperature increase in the peripheral portion of the semiconductor wafer W and to uniformly heat the inside thereof. Further, during cooling, heat is not accumulated in the ring-shaped support body 41 so that the peripheral portion is not rapidly cooled. As a result, the in-plane of the semiconductor wafer W can be uniformly heated and cooled without a temperature gradient.

Further, the cooling device 50 is the heating furnace 2
0 and the above-mentioned reaction container 30 are configured to forcibly cool the inside of the reaction container 30 by circulating cold air in the space 60. That is, the cooling device 50 includes an exhaust fan 52 connected to an exhaust port 23 formed at the center of the upper surface of the heating furnace 20 through an exhaust duct 51, a lower end of the void 60 and a lower end of the heating furnace 20. A plurality of intake ports 53 formed at equal intervals on the periphery, a communication duct 54 communicating with these intake ports 53, and an external air connected to the communication duct 54 to the intake port 53 via the communication duct 54. An air supply fan 55 for supplying air is provided, and an ascending airflow of air is formed in the space 60 by the cooperation of the exhaust fan 52 and the air supply fan 55, as shown by an arrow B in FIG. It is configured to cool the inside of the reaction container 30 by a rising temperature, for example, at a temperature decreasing rate of 30 to 100 ° C./min. If the rate of temperature decrease is less than 30 ° C./minute, the cooling rate is slow, which may cause unnecessary heat to be applied to the semiconductor wafer W.
If the temperature exceeds 00 ° C./minute, the entire surface of the semiconductor wafer W cannot be forcibly and evenly cooled through the ring-shaped support body 41, which may cause a temperature gradient in the surface, which is not preferable.
In addition, the heat treatment boat 40 is provided at each of the intake ports 53.
Supply nozzle 5 reaching the ring-shaped support 41 at the bottom of the
6 is attached, and these air supply nozzles 56 are configured to form a uniform updraft around the void 60. The exhaust duct 51 communicates with a common duct 70 in the factory, and the high temperature air exhausted from the gap 60 by the exhaust fan 52 and the air supply fan 55 is cooled by the heat exchanger 57 while exhausting the exhaust duct 70. Fan 7
1 is configured to discharge to the outside as shown by an arrow C in FIG. Further, shutters 58 and 59 are provided at the exhaust port 23 and the intake port 53, respectively, and during the heat treatment, the shutters 58 and 59 are closed to seal the gap 60 so that the reaction container 30 can be efficiently heated. Is configured. The shutter 58 of the exhaust port 23 is made of, for example, a heat-resistant material such as quartz, and the shutter 59 of the air supply port 53 is made of, for example, stainless steel or fluorine resin.

Next, the heat treatment method of this embodiment will be described for the case where the BPSG film is formed on the semiconductor wafer W using the low pressure CVD apparatus. A wiring layer 2 made of titanium silicide or the like is formed on the semiconductor wafer W used in this embodiment, as shown in FIG. In the heat treatment method of this embodiment, heat treatment is performed as shown in FIG. To this end, first, the reaction vessel 30 is heated by the heating furnace 20 to set the internal temperature to, for example, 400 ° C.
The heat treatment boat 40 is loaded into the reaction vessel 0 and the inside of the reaction vessel 30 is sealed with the flange 45.
The dummy wafers at the upper and lower ends are set in the reaction container 30. Subsequently, the air in the reaction container 30 is exhausted to the exhaust pipe 33B.
Then, the temperature inside the reaction vessel 30 is heated by the resistance heating element 21 of molybdenum disilicide at a temperature rising rate of, for example, 100 ° C./min as shown by in FIG. The internal temperature is set to 600 ° C. as shown in FIG. At this temperature, 50 sccm of TEOS, 100 sccm of PH3, 7.5 sccm of TMB, and 10 sccm of oxygen were supplied from each gas introduction pipe 33C to maintain a vacuum degree of 0.8 Torr, and in this state, as shown by in FIG. These reactive gases are reacted on the surface of the semiconductor wafer W for several minutes to deposit the reactive organisms on the surface of the semiconductor wafer W, that is, on the surface of the wiring layer 2 and the surface of the groove formed between the wiring layers 2 and 2, respectively. Then, as shown in FIG. 4A, a BPSG film 1 of, for example, 4000 angstrom is formed on each surface.

After that, the reactive gas in the reaction vessel 30 is exhausted through the exhaust pipe 33B and replaced with an inert gas such as nitrogen, and then heated at a temperature rising rate of 100 ° C./min as shown in FIG. And set the internal temperature to 900 ° C, and at that temperature B
Reflow the PSG film 1. That is, the semiconductor wafer W is heated at 900 ° C. for several minutes as shown by in FIG.
The G film 1 is heated and melted, and the peripheral molten BPSG is poured into the groove between the wiring layers 2 and 2 to form a tapered groove, as shown in FIG. To make it easy to form a film.

After reflowing for several minutes as shown in FIG. 3, the shutters 58 and 59 are opened, the exhaust fan 52 and the air supply fan 55 are driven, and the communication duct 54,
Air having a normal temperature is supplied into the space 60 into the heating furnace 20 through the plurality of air inlets 53 and the plurality of air supply nozzles 56 to generate a uniform upward air flow around the entire circumference of the reaction vessel 30 as indicated by an arrow B in FIG. While being formed as shown, the air whose temperature has been raised inside is exhausted while being cooled to the exhaust duct 70 via the exhaust port 23, the exhaust duct 51 and the heat exchanger 57, and is exhausted to the outside by the exhaust fan 71. Thus, the heating furnace 20 and the reaction container 30
Cold air is evenly distributed throughout the gaps 60 between the reaction vessels 30 to forcibly and evenly cool the entire reaction vessel 30, and the inside of the reaction vessel 30 is cooled at, for example, 50 ° C./min as shown in FIG. To the reaction temperature of the reactive gas of 600 ° C., the solidified BPSG film 1 is solidified.

After the BPSG film 1 is solidified, each of the above-mentioned reactive gases is again supplied into the reaction container 30 under the same condition at the temperature of 600 ° C. shown in FIG. 3 and the semiconductor wafer W shown in FIG. 4000 Angstrom BPSG on the surface
After the film 1 was formed as shown in FIG. 3C, the reactive gas was replaced with an inert gas under the same conditions as described above, and the internal temperature was set to 100 ° C. until the internal temperature reached 900 ° C.
When the BPSG film 1 is reflowed at a temperature shown in FIG.
The shallow groove of the BPSG film 1 indicated by is filled with the surrounding molten BPSG as shown in FIG. 3D, and the BPSG film 1 on the surface of the semiconductor wafer W is flattened. After that, shutter 5
After opening 8, 59 and forcibly cooling by the cooling device 50 at the temperature decrease rate of 50 ° C./min as shown in FIG. 3, the heat treatment boat 40 is unloaded, and the semiconductor wafer W of the heat treatment boat 40 is not processed. After exchanging with the thing, this heat treatment boat 40 is loaded. At this time, the heating furnace 20 at 600 ° C
Radiates heat to lower the temperature to about 400 ° C., and after the next loading of the semiconductor wafer W, the series of operations described above can be repeated under the same conditions.

As described above, according to this embodiment, the BPSG film 1 is formed twice in the same reaction container 30 without unloading the semiconductor wafer W from the reaction container 30, and Since the BPSG film 1 is reflowed after the film formation, even if the semiconductor wafer W has the wiring layer 2 having a high aspect ratio, it is possible to perform uniform film formation without deposit overhang.
When the film 1 is reflowed, the BPSG film 1 can be planarized without generating voids between the wiring layers 2 and 2,
Moreover, since the semiconductor wafer W does not come into contact with the air during the two film formations, oxygen or other impurities in the air are not mixed into the BPSG film 1, and the BPSG film having excellent electrical and mechanical film quality is obtained. The film 1 can be formed, and the yield of heat treatment can be increased.

In this embodiment, a resistance heating element 21 of molybdenum disilicide is used as an external heater to heat at a temperature rising rate of 100 ° C./minute, and a cooling device 50 is used to heat the void 60.
Since an ascending air current of cold air is created to forcibly cool at a temperature lowering rate of 50 ° C./min, the time required for two-step film formation and reflow can be significantly reduced compared to the conventional case.
The throughput of heat treatment can be improved. still,
In the case of the conventional low pressure CVD apparatus, the heater has a temperature rising rate of, for example, about 5 ° C./minute, and the cooling capacity is not sufficient. Therefore, it was difficult to carry out the film forming operation and the reflow operation separately.

Further, in this embodiment, the peripheral portion of the semiconductor wafer W is supported by the ring-shaped support 41 having a large heat capacity, and the semiconductor wafer W is heated and cooled via the ring-shaped support 41. Even if the upper and lower semiconductor wafers W adjacent to the semiconductor wafer W supported by the ring-shaped support 41 impede the heating and heat dissipation functions, the ring-shaped support 41 having a large heat capacity increases the temperature rise rate of the peripheral portion of the semiconductor wafer W and The temperature falling rate can be delayed to uniformly heat and cool the surface, and as a result, the semiconductor wafer W can be uniformly heat-treated in a short time.

In the above-mentioned embodiment, the case where the BPSG film forming step and the reflow step are performed twice has been described, but each step may be performed three times or more if necessary. It is effective when the ratio becomes higher and higher, and the same effect as the above embodiment can be expected. Further, the present invention is not limited to the film formation of BPSG.

Further, although the description has been given of the case where the resistance heating element 21 of molybdenum disilicide is used as the external heater to increase the temperature rising rate, the material of the resistance heating element is not limited to molybdenum disilicide, for example, 100. Any temperature can be used as long as the temperature inside the reaction container 30 can be raised in a short time, such as a temperature rising rate of ° C / min. Further, the cooling device 50 is not limited to the structure of the above-described embodiment, and may be any device that can cool down the temperature in a short time, for example, a cooling rate of 50 ° C./min.

Further, the supporting member for supporting the semiconductor wafer W is not limited to the ring-shaped supporting member 41 of the above-mentioned embodiment, and the supporting member in the present invention is formed of a material and a shape having a large heat capacity. I wish I had it.

[0033]

According to the first aspect of the present invention, since the film forming step, the flattening step and the cooling step are continuously performed at least twice in the same reaction vessel, a high aspect ratio is achieved. Even if it is, a uniform film can be formed and the surface of the object to be processed can be flattened without generating voids, and a film with excellent electrical and mechanical properties without mixing impurities can be applied to the object to be processed. It is possible to provide a heat treatment method which can be formed into

According to the invention of claim 2 of the present invention, in the invention of claim 1, the inside of the reaction vessel is 5
Since the temperature in the reaction vessel is increased at a temperature increase rate of 0 to 200 ° C./min and the temperature inside the reaction vessel is decreased at a temperature decrease rate of 30 to 100 ° C./min, a heat treatment method that shortens the heat treatment time and improves throughput is provided. be able to.

Further, according to the invention of claim 3 of the present invention, in the invention of claim 1 or 2,
Since the heater made of molybdenum disilicide is used and the inside of the reaction vessel is forcibly cooled, it is possible to provide a heat treatment method which can shorten the heat treatment time and improve the throughput.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the peripheral portion of the object to be processed is supported by a support member having a large heat capacity. Then, since the object to be processed is heated and cooled through this support member to uniformly heat and cool the object to be processed, the temperature rising rate and the temperature decreasing rate of the peripheral edge of the object to be processed are delayed and the in-plane It is possible to uniformly heat and cool, and as a result, it is possible to provide a heat treatment method capable of uniformly heat-treating the entire object in a short time.

[Brief description of drawings]

FIG. 1 is a reduced pressure C suitably used in the heat treatment method of the present invention.
It is sectional drawing which shows the principal part of an example of a VD apparatus.

FIG. 2 is an enlarged sectional view showing a support member for a semiconductor wafer of a heat treatment boat of the low pressure CVD apparatus shown in FIG.

FIG. 3 is a diagram showing the course of processing temperature showing a preferred embodiment of the heat treatment method of the present invention.

4 is an enlarged view showing a semiconductor wafer showing a process of processing the semiconductor wafer by the heat treatment method shown in FIG. 3, where FIG. 4 (a) is a sectional view showing a state immediately after film formation, and FIG. 4 (b). Is a cross-sectional view showing a state after reflowing the film of FIG.
6C is a cross-sectional view showing the state after the second film formation in the state of FIG. 7B, and FIG. 7D is a cross-sectional view showing the state after reflowing the coating film of FIG. Is.

FIG. 5 is an enlarged view of a semiconductor wafer showing a process of processing the semiconductor wafer by a conventional heat treatment method.
Is a cross-sectional view showing a state immediately after film formation, and FIG. 8B is a cross-sectional view showing a state after reflowing the coating film of FIG.

[Explanation of symbols]

 20 heating furnace 21 resistance heating element (external heater, molybdenum disilicide) 30 reaction vessel 40 heat treatment boat (holding tool) 50 cooling device 60 void

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Fujita 1-241, Machiya, Shiroyama-cho, Tsukui-gun, Kanagawa Prefecture Tokyo Electron Tohoku Co., Ltd. Sagami Business Office

Claims (4)

[Claims] 1. A predetermined reactive gas is supplied into a reaction container heated by an external heater to a predetermined reaction temperature, and a plurality of objects to be processed are held by a holder in the reaction container. After depositing the reaction product of the reactive gas to form a coating, the reactive gas is replaced with an inert gas, and the inside of the reaction vessel is heated to a predetermined temperature by the external heater to melt the coating. After flattening, the reaction vessel is cooled to the reaction temperature, and the coating film forming step is continuously performed.
A heat treatment method characterized in that the flattening step and the cooling step are performed at least once. 2. The inside of the reaction vessel is heated at a temperature rising rate of 50 to 200 ° C./min, and the inside of the reaction vessel is 30 to 100.
The cooling is performed at a temperature decreasing rate of ° C / min.
The heat treatment method described in. 3. The method according to claim 1, wherein molybdenum disilicide is used as the external heater to heat the inside thereof, and an air flow is formed on the outer peripheral surface of the reaction vessel to cool the inside thereof. 2. The heat treatment method as described in 2. 4. The object to be processed is supported by a supporting member having a large heat capacity, and the object to be processed is heated and cooled through the supporting member. The heat treatment method according to one.