JP3226643B2 - Semiconductor device manufacturing method and 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 an apparatus for manufacturing a semiconductor device.
Alternatively, a film or layer of a semiconductor material, an insulating material, a metal, a superconducting material, etc. is formed on a semiconductor wafer such as a logic circuit IC, a thin film transistor IC using a reactive gas, or is diffused in the presence of an atmospheric gas to improve the film quality. ,
In the manufacture of a semiconductor device for performing a heat treatment of a semiconductor wafer such as a film flattening, it relates to a proposal to reduce contamination caused by generation of particles due to a reaction gas and / or to keep a diameter of a heating furnace small when flowing a large amount of gas. .

[0002] In the present invention, the term "reactive gas" refers to those in which gases react or decompose to form the above-mentioned film or layer, and those in which the gas reacts with the wafer to form the above-mentioned film or layer. Refers to the meaning of reactive gas. The gas refers to not only ordinary atoms and molecules, but also ions or reactive species in an active state. The "carrier gas" is not intended to react with the wafer as described above, and may be an inert gas or a nitrogen gas or a hydrogen gas depending on the type of heat treatment.

[0003]

2. Description of the Related Art The exhaust treatment of a heating furnace for manufacturing semiconductor devices to which the present invention relates is described in Japanese Patent Application Laid-Open No. 53-511.
No. 87, Japanese Patent Application Laid-Open No. 65-20282, there is a significant drop in the temperature at the exhaust part provided at the end of the reaction tube, so that the film quality produced by the reaction is significantly different from that on the wafer. The resulting particles fell into the reaction chamber.

FIG. 2 shows that the present applicant has filed a Japanese Patent Application No. Hei 4-308047.
No. 1 shows a vertical heating furnace, 2 shows a single furnace body, and 1 shows a vertical heating furnace.
Reference numeral 3 denotes a gas inlet pipe provided at a lower portion of the furnace body, 4 denotes a wafer holder, 5 denotes a wafer vertically placed on the wafer holder 4, 6 denotes a jig for detachably holding the wafer holder 4, and 7 denotes a holding jig. , A baffle plate 8 and a heating device 10 such as a heating element. Reference numeral 11 denotes an exhaust pipe drawn along the furnace body from a hole provided at the top of the furnace body 2 to a lower portion thereof, and 12 denotes an insulating material in which a heating device is embedded.

[0005] The lower half of FIG. 2 is a place for accommodating 4 to 7 such as wafers before and after the heat treatment, and 15 is a jig for loading / unloading the wafer which moves up and down along the guide rod 16. 17 is a shielding tube for reducing heat radiation of the wafer, 18 is a driving means for moving the shielding tube 17 up and down along a guide rod 19, 20 is a roller for guiding up and down,
Reference numeral 21 denotes a gas introduction pipe for introducing an atmosphere gas for preventing oxidation or the like of the wafer during cooling into the shielding cylinder 17.

Further, the outer tube of the double tube has a furnace body structure with a closed top, and the inner tube has a double tube structure in which an annular gap between the inner and outer tubes communicates with the furnace space at the upper end thereof. An apparatus for manufacturing a semiconductor device that discharges a reaction gas through an annular gap using a furnace is also known.

It is said that a 64M DRAM requires a 12-inch large-diameter wafer (“Nikkei Micro Devices”, November 1992), and as the degree of integration of semiconductor devices becomes higher as described above. The following is required. (A) The size and number of particles to be managed must be reduced (reduced). (B) The increase in equipment cost is suppressed by performing small batch or single wafer processing. (C) In the future, it is expected that the life cycle of a semiconductor will not change every generation as in the past, but three generations such as 1M, 16M, and 64M-DRAM will coexist. Production is expected to occur, so it is necessary to adapt to small-lot production.

[0008]

In the case of the ordinary low-pressure CVD method, the pressure inside the furnace body is, for example, 0.1 to 1.0 torr.
The gas flow rate when forming a film on a 6-inch wafer under the above conditions is about 300 to 600 m ³ / hour, but in order to achieve uniform film formation on the wafer surface which is required as the diameter of the wafer increases and the number of wafers increases. Therefore, it is necessary to increase the gas flow rate, for example, to 1500 m ³ / hour. However, as the flow rate is increased, it is necessary to increase the diameter of the furnace body and the diameter of the vertical furnace, which results in a problem that the volume and weight of the entire apparatus increase.

Further, in the conventional semiconductor manufacturing apparatus shown in FIG. 2, since the heating effect of the heating device 10 is insufficient at the end of the exhaust pipe 11 on the furnace body side, the temperature is higher than that of the reaction section where the wafer 5 is placed. Got lower. Generally, Si, S
Since the higher the temperature, the better the film quality of various CVD films such as iO ₂ and SiN is, the film quality adhering to the furnace wall at the furnace body end of the exhaust pipe 11 is poor, easily falling off as particles and falling into the reaction section, Therefore, the problem that the inside of the furnace was contaminated also occurred, and it was found that this would be a serious obstacle to the improvement of the integration degree of ICs in the future.

In the above-described semiconductor manufacturing apparatus having a single tube structure, when the gas is exhausted at the upper portion of the reaction tube, the temperature of the reaction gas changes rapidly at the upper end of the inner tube, so that particles are easily generated at this location. The particles fall or flow into the reaction space in the furnace, and the semiconductor wafer is easily contaminated by the particles. The double tube is excellent in particle measures, but the quartz tube is expensive, so a large tube that requires two tubes, a reaction tube corresponding to the diameter of the wafer and an outer tube larger than this. Double tube equipment for wafers is very expensive. Further, in the double tube apparatus, when plasma self-cleaning is performed, cleaning between the tubes proceeds, and it is difficult to clean the inside of the reaction tube. Therefore, the use of a double tube having such a problem was avoided, and the use of a single tube capable of processing semiconductors using only the inner tube was considered.

[0011] In addition, as described above for CVD and the like by the reaction between gases, in the case of a reaction between a substrate and a gas such as nitridation of a Ti sputtered film by ammonia or nitrogen and oxidation of Si by oxygen, the reaction of the gas is a wafer. Although the above-mentioned problem does not occur because it occurs only in the disposition region, for example, CVD
When the i ₃ N ₄ film is formed, a reaction of these gases occurs to generate a secondary reaction product, and particles generated by the secondary reaction product are expected to lower the yield of highly integrated semiconductor devices in the future. .

Accordingly, the present invention provides a method of manufacturing a semiconductor device and a method of manufacturing a semiconductor device capable of preventing an increase in the diameter of a heating furnace and reducing generation of particles when a large amount of a reaction gas or a carrier gas is required to flow. It is intended to provide a device.

[0013]

The first aspect of the method of manufacturing a semiconductor device according to the present invention is that a semiconductor wafer is subjected to a heat treatment in a reaction section in a heating furnace in the presence of a reaction gas and an exhaust section communicating with the reaction chamber. In the method of manufacturing a semiconductor device, wherein the unreacted gas is exhausted from above, and the unreacted gas is meandered up and down one or more times above the heating furnace and heated, and the unreacted gas is heated from substantially above the reaction section. Out of the semiconductor manufacturing apparatus. The heating in the upper portion is performed so that a film substantially the same as the lower reaction portion grows as a stable film on the wall of the exhaust portion so that particles are not generated. The second of the method for manufacturing a semiconductor device of the present invention is a semiconductor device in which a semiconductor wafer is subjected to heat treatment in a reaction section in a heating furnace in the presence of a carrier gas, and the carrier gas is exhausted from an exhaust section communicating with the reaction chamber. In the manufacturing method, the carrier gas is meandered up and down one or more times above the heating furnace and heated, and the carrier gas flows out of the semiconductor manufacturing apparatus from substantially above the reaction section. I do.

Further, the semiconductor device manufacturing apparatus of the present invention (hereinafter referred to as “apparatus” refers to a semiconductor device manufacturing apparatus) is a device for maintaining exhaust gas once above a reaction section of a heating furnace for heat-treating a semiconductor wafer. A meandering path for meandering up and down is formed above the heating furnace, an exhaust port of the exhaust unit is located substantially above the reaction unit, and a heating device for heating the exhaust unit is provided outside the exhaust unit. It is characterized by being provided in. In this heating device, a film substantially the same as the lower reaction portion is grown as a stable film on the wall of the exhaust portion, and heating is performed so that particles are not generated. The heating temperature can be approximately the same as or slightly higher than the reaction temperature.

Hereinafter, the configuration and embodiments of the present invention will be described. The exhaust part which is a feature of the present invention is that gas (hereinafter, simply referred to as “gas” when collectively referring to “reaction gas” and “carrier gas”) flows upward once, then flows downward, and performs one meandering. The main point is that a meandering channel for meandering two or more times is formed above the heating furnace, and that an outlet for discharging gas out of the semiconductor manufacturing apparatus is located substantially above the reaction chamber. . In the upward flow path, the gas is flowed upward for a certain distance so as to reduce the resistance of the gas flow, instead of warping the flow path immediately after leaving the heating furnace as in the conventional apparatus shown in FIG. If the exhaust section is simply composed of the upward flow path, if particles are generated there, there is a risk of falling into the heating furnace.Therefore, a downward flow path is provided following the upward flow path so that the particles do not easily return to the reaction section. I do. It is difficult for the particles generated in the downward flow path to enter the upward flow path against the gas flow, and even if dropped, they remain in the flow path and do not contaminate the reaction chamber.

It is important that the above-mentioned flow path forms a meandering path vertically, and there is no effect in the meandering in the horizontal direction. The upper and lower meandering paths are preferably meandering in the vertical direction, but some inclination is allowed. Forming the meandering channel above the heating furnace avoids increasing the diameter or thickness of the device. This is necessary for uniformly heating the semiconductor device and for downsizing the equipment. The diameter of the upward channel immediately after the reaction chamber is not particularly limited,
It can be the same, smaller or larger than the diameter of the reaction chamber. If the diameter of the upward flow path is the same as the diameter of the reaction chamber, it is possible to dimensionally arrange the wafer, but the unreacted gas processing section is simply used as an exhaust section without disposing the wafer. This is very important. In addition, the meandering channel may be a single tube meandering, or a gap between multiple tubes may be used as the meandering channel.

As the number of meandering increases, the risk of particles generated in places where the temperature changes greatly against the inside of the furnace against the gas flow decreases. Therefore, when the number of meandering is small, the exhaust outlet needs to be provided at the end of the downward flow path, but when the number of meandering increases, the exhaust outlet may be provided at any position.

Further, since the outlet of the gas of the exhaust part of the present invention to the outside of the apparatus is substantially above the reaction chamber of the wafer, the total length of the flow path of the exhaust part is reduced, and the gas flow resistance is reduced. (The conductance is large). Further heating the exhaust section eliminates temperature drop in the exhaust section,
The film quality of the film that may be generated in the exhaust unit is prevented from deteriorating.

The heating temperature of the gas in the exhaust gas is preferably substantially the same as or higher than the temperature of the heat treatment, so that the generation of particles is extremely reduced.

The method of the present invention is suitable for processing large diameter wafers by flowing a large amount of gas.
A semiconductor wafer having a diameter of 6 inches or more is introduced into the reaction section where the reaction gas or the reaction gas and the carrier gas are heated, and the reaction tube is pumped using a pump having an exhaustion capacity of 600 to 2000 m ³ / hour or more. The internal pressure is 0.1-1.
A thin film can be formed on a semiconductor wafer while adjusting to 0 Torr.

[0021]

In the past, the exhaust portion used an annular space of a double-pipe heating furnace or simply used an exhaust pipe extending along the furnace wall of a downward heating furnace (FIG. 2). According to the first, second and fifth aspects of the present invention, the generation of particles is suppressed by one or more meandering paths which are heated, and the wafer is not disposed in the meandering path but is guided to the apparatus from substantially above the reaction chamber. This reduces the flow resistance of the gas, thereby suppressing an increase in the diameter of the device.

According to the third aspect, the heating temperature of the heating means can be set to be the same as or higher than the heating temperature of the heating furnace, thereby making it more difficult to generate particles.
According to the fourth and sixth aspects, in the case where the number of meandering is small, particles are likely to be generated at the discharge port where the temperature changes drastically, so that the discharge port is provided below the meandering flow path and the particles constitute the flow path. They collect at the bottom of the box to prevent contamination.

The present invention will be described below with reference to an embodiment shown in the drawings.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus shown in FIG. 1 has an extension 25 formed by narrowing a cross section of a heating furnace above a reaction section 10a (an area where the wafer 5 is disposed) of the heating furnace for heat-treating the semiconductor wafer 5.
Is formed above the heating furnace 1, the exhaust port 27 of the exhaust section is located substantially above the reaction section 1a, and a heating device 28 for heating the exhaust section is provided outside the exhaust section. Things. The device components other than 25, 27, 28 and 30 have the same functions as those of the conventional device of FIG. 2 and correspond to those denoted by the same reference numerals, and may be omitted or changed as necessary. And other known components can be added.

The device of FIG. 1 has an exhaust port 27 below the exhaust section; the exhaust section is constituted by a double tube with respect to the central axis of the furnace; the diameter of the exhaust section is approximately equal to the diameter of the furnace 1. Such points correspond to the further limited embodiments, but these limitations are not essential. In addition, the extension part 25 and the outer pipe 29 of a double pipe correspond to an exhaust part.

FIG. 3 shows an embodiment of a device having a four-tube structure, which is basically different from the device of FIG. 1, but the other points are the same as those of the device of FIG. . The apparatus shown in FIG. 3 can make the height of the exhaust portion lower than that of the apparatus shown in FIG. 1, and can more effectively prevent the contamination by particles by increasing the number of flow paths in which the gas flow descends. Furthermore, it is also possible to use a quintuple tube or a hexatube.

FIG. 4 shows an embodiment in which the present invention is applied to an apparatus for placing the wafer 5 horizontally. In the drawing, reference numeral 30 denotes a wafer holder, 32 denotes a rotating shaft integrated with the wafer holder 30, and 33 denotes a shaft. A motor for rotating the rotating shaft 32,
34 is a bearing for receiving the rotating shaft 32, 35 is a gas introducing pipe slidably in contact with the bearing 34 and penetrates through a hollow portion in the rotating shaft 32, and 36 is fixed to the tip of the gas introducing pipe and is radially 40 is a magnet or an electromagnet, 40
Is a baffle provided between the extension 1 and the extension 25 so that the gas flow in the reaction section 1a is uniform in the horizontal direction.
The other elements of the device are the same as those described with reference to FIGS.

The conditions for forming layers or films or the conditions for heat treatment performed by the above-described apparatus are known, but differ in that the gas flow rate can be increased. This flow rate varies depending on the type of gas, the number of wafers to be processed, and the like, but can be twice or more with the same furnace body diameter as in the conventional apparatus.

[0029]

As described above, the present invention is intended to cope with recent production of highly integrated semiconductor devices by reducing the number of particles and enabling single-wafer processing of large-diameter wafers. Greatly contributes to the manufacture of semiconductor devices.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a semiconductor manufacturing apparatus of the present invention.

FIG. 2 is a diagram showing an embodiment of a conventional semiconductor manufacturing apparatus.

FIG. 3 is a diagram showing another embodiment of the semiconductor manufacturing apparatus of the present invention.

FIG. 4 is a view showing still another embodiment of the semiconductor manufacturing apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating furnace 1a Reaction part 2 Single furnace body 3 Gas inflow pipe 4 Wafer holder 5 Wafer 6 Wafer holder holding jig 7 Rotating mechanism of holding jig 10 Heating device 11 Exhaust pipe 15 Wafer loading / unloading jig 17 Shielding cylinder REFERENCE SIGNS LIST 18 drive means 19 drive means 20 roller 21 gas introduction pipe 25 extension 27 exhaust port 28 heating device 29 outer pipe 30 gas flow direction change area

Claims (7)

(57) [Claims] 1. A method for manufacturing a semiconductor device, comprising: performing a heat treatment on a semiconductor wafer in a reaction section in a heating furnace in the presence of a reaction gas, and exhausting an unreacted gas from an exhaust section communicating with the reaction chamber. Manufacturing the semiconductor device, wherein the gas is meandered up and down one or more times above the heating furnace and heated, and the unreacted gas flows out of the semiconductor manufacturing apparatus from substantially above the reaction section. Method. 2. A method of manufacturing a semiconductor device, comprising: performing a heat treatment on a semiconductor wafer in the presence of a carrier gas in a heating furnace; and exhausting the carrier gas from an exhaust unit communicating with the reaction chamber. 1 above
A method of manufacturing a semiconductor device, wherein the carrier gas is meandered up and down at least once and heated to cause a carrier gas to flow out of the semiconductor manufacturing apparatus from substantially above the reaction section. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the upper heating temperature is substantially equal to or higher than the temperature of the heat treatment. 4. The method for manufacturing a semiconductor device according to claim 1, wherein the unreacted gas or the carrier gas flows out from a gas descending portion. 5. A meandering path for making the exhaust gas meander up and down one or more times above a reaction part of a heating furnace for performing a heat treatment of a semiconductor wafer is formed above the heating furnace.
An apparatus for manufacturing a semiconductor device, wherein an exhaust port of the exhaust section is located substantially above the reaction section, and a heating device for heating the exhaust section is provided outside the exhaust section. 6. The apparatus for manufacturing a semiconductor device according to claim 5, wherein said exhaust port is formed in a gas flow descending portion of said meandering path. 7. The semiconductor device manufacturing apparatus according to claim 5, wherein said meandering path is constituted by one pipe or multiple pipes.