JP4456727B2 - Semiconductor device manufacturing method and substrate processing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing method, and more particularly to technology for preventing oxidation and contamination of a substrate to be processed. For example, in a semiconductor device manufacturing process, an annealing process, an oxide film forming process, a diffusion process, and a film forming process on a semiconductor wafer. The present invention relates to an effective material that can be used for heat treatment such as treatment.
[0002]
In general, a batch type vertical hot wall heat treatment apparatus (furnace) is used to perform heat treatment such as annealing, oxide film formation, diffusion and film formation on a semiconductor wafer (hereinafter referred to as a wafer) in a semiconductor device manufacturing process. Hereinafter, the heat treatment apparatus is widely used.
[0003]
As a conventional heat treatment apparatus of this kind, there is one described in Japanese Patent No. 2681055. In this heat treatment apparatus, a boat exchange device is disposed between the wafer transfer device and the space immediately below the process tube, and a pair (two) of boats are placed on the rotary table of the boat exchange device, A pair of boats rotate 180 degrees around the rotary table, whereby an unprocessed boat and a processed boat are exchanged. That is, in this heat treatment apparatus, while one boat (first boat) holding a wafer group is being processed in the process chamber of the process tube, a new wafer is transferred to the other boat (second boat). It is transferred by a loading device.
[0004]
[Problems to be solved by the invention]
In general, the film formation time of the heat treatment apparatus is 1 to 2 hours, although it depends on the type of film processed by the heat treatment apparatus. On the other hand, the time required to transfer a new wafer onto the boat by the wafer transfer device is about 12 minutes for 150 wafers. Therefore, in the above-described heat treatment apparatus, the new wafer group transferred to the second boat waits outside the processing chamber for a long period of about 1 to 2 hours until the processing of the first boat is completed. become.
[0005]
However, when a new wafer group transferred to the second boat is exposed to the atmospheric air outside the processing chamber for a long period of time, an oxide film (hereinafter referred to as a natural oxide film) unintentionally controlled is exposed to the atmosphere on the wafer surface. It is formed by oxygen and moisture. Since this natural oxide film affects the variation in the film thickness processed on the wafer and increases the contact resistance, a semiconductor integrated circuit device (hereinafter referred to as an IC) manufactured by the wafer is highly integrated. It adversely affects quality (accuracy, lifetime, etc.), performance (calculation speed, etc.) and reliability.
[0006]
An object of the present invention is to provide a substrate processing method capable of reducing the standby time in the air atmosphere and preventing the generation of a natural oxide film.
[0007]
[Means for Solving the Problems]
The substrate processing method according to the present invention includes a process tube in which a processing chamber is formed, a boat that enters and exits the processing chamber and carries a plurality of substrates in and out, and the processing chamber that receives the plurality of substrates from the boat. A substrate processing method in which a substrate processing apparatus including a substrate transfer apparatus that receives and transfers outside is used, wherein at least two boats are sequentially used.
The substrate transfer time by the substrate transfer device to the other boat to be processed next to the one boat being processed is the substrate transfer time to the other boat and the one boat. It is calculated based on the processing elapsed time.
[0008]
According to the above-mentioned means, since the substrate transfer start time to the boat is automatically determined according to the processing elapsed time, the waiting time of the substrate in the air atmosphere can be set to the shortest. Generation of an oxide film can be prevented.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0010]
In the present embodiment, the substrate processing method according to the present invention is carried out using a batch type vertical hot wall diffusion / CVD apparatus (hereinafter referred to as diffusion CVD apparatus) shown in FIG. It is configured and used for performing diffusion and CVD processes such as annealing, oxide film formation, diffusion and film formation on a wafer as a substrate.
[0011]
As shown in FIG. 1, a diffusion CVD apparatus 1 in which the diffusion CVD method according to the present embodiment is implemented includes a housing 2 formed in a rectangular parallelepiped box shape in plan view. A clean unit 3 is installed in the rear part of the left side wall of the housing 2 (the left and right front and rear are based on FIG. 1). The clean unit 3 supplies clean air to the inside of the housing 2. Yes. A heat treatment stage 4 is set at substantially the center of the rear part inside the housing 2, and a standby stage (hereinafter referred to as a standby stage) 5 in which an empty boat is temporarily placed on the front and rear of the left side of the heat treatment stage 4 to wait. In addition, a stage (hereinafter referred to as a cooling stage) 6 for temporarily placing the processed boat and cooling it is set. A wafer loading stage 7 is set in the approximate center of the front part inside the housing 2, and a pod stage 8 is set in front of it. A notch aligner 9 is installed on the left side of the wafer loading stage 7. Hereinafter, the configuration of each stage will be described in order.
[0012]
As shown in FIGS. 5 and 6, the process tube 11 integrally formed in a cylindrical shape using quartz glass at the upper part of the heat treatment stage 4 and having an opening at the lower end is arranged so that the center line is vertical. It is arranged vertically. A cylindrical hollow portion of the process tube 11 forms a processing chamber 12 into which a plurality of wafers held concentrically aligned by a boat are loaded, and a lower end opening of the process tube 11 is a wafer as a substrate to be processed. The furnace port 13 for taking in and out is comprised. Therefore, the inner diameter of the process tube 11 is set to be larger than the maximum outer diameter of the wafer to be handled.
[0013]
The lower end surface of the process tube 11 is in contact with the upper end surface of the manifold 14 with the seal ring 15 interposed therebetween, and the process tube 11 is supported vertically by the manifold 14 being supported by the housing 2. ing. An exhaust pipe 16 is connected to a part of the side wall of the manifold 14 so as to communicate with the processing chamber 12, and the other end of the exhaust pipe 16 is a vacuum exhaust device for evacuating the processing chamber 12 to a predetermined degree of vacuum. (Not shown). A gas introduction pipe 17 is connected to the other part of the side wall of the manifold 14 so as to communicate with the processing chamber 12, and the other end of the gas introduction pipe 17 is a gas for supplying a gas such as a raw material gas or nitrogen gas. It is connected to a supply device (not shown).
[0014]
A heater unit 18 is concentrically provided outside the process tube 11 so as to surround the process tube 11, and the heater unit 18 is supported vertically by the housing 2. The heater unit 18 is configured to uniformly heat the entire processing chamber 12.
[0015]
A cap 19 formed in a disk shape substantially equal to the outer diameter of the process tube 11 is concentrically disposed just below the process tube 11 in the heat treatment stage 4. The cap 19 is formed by an elevator 20 configured by a feed screw mechanism. It is raised and lowered in the vertical direction. The cap 19 supports the boat 21 by vertically standing on the center line. In the present embodiment, two boats 21 are used.
[0016]
As shown in FIGS. 5 and 6, the two boats 21, 21 are arranged vertically between a pair of end plates 22, 23 and both end plates 22, 23 in the vertical direction. In addition, a plurality of (three in this embodiment) holding members 24 are provided, and each holding member 24 is arranged at equal intervals in the longitudinal direction so as to be opened in the same plane. By inserting the wafers W between the plurality of holding grooves 25, the plurality of wafers W are configured to be held in a state where they are aligned horizontally and aligned with each other.
[0017]
A heat insulating cap portion 26 is formed under the lower end plate 23 of the boat 21, and a column 27 formed in a columnar shape having a smaller diameter than the outer diameter of the heat insulating cap portion 26 is formed on the lower surface of the heat insulating cap portion 26. It protrudes vertically downward. A space into which an arm of a boat transfer device, which will be described later, is inserted is formed on the lower surface of the support column 27 on the lower surface of the heat insulating cap unit 26, and an engagement portion for engaging the arm with an outer peripheral portion on the lower surface of the support column 27. 28 is configured. A base 29 is horizontally provided on the lower surface of the column 27.
[0018]
As shown in FIG. 1, a boat transfer device 30 is installed between the standby stage 5 and the cooling stage 6 to transfer the boat 21 between the heat treatment stage 4, the standby stage 5, and the cooling stage 6. Yes. As shown in FIG. 7, the boat transfer device 30 is configured by a SCARA robot, and a pair of first arms 31 that reciprocate by about 90 degrees in a horizontal plane and A second arm 32 is provided. Both the first arm 31 and the second arm 32 are formed in an arc shape, and are engaged with the engaging portion 28 of the heat insulating cap portion 26 from below while being inserted outside the column 27 of the boat 21. The entire boat 21 is supported vertically.
[0019]
As shown in FIGS. 1 and 7, the standby stage 5 is provided with a standby table 33 that vertically supports the boat 21, and the first arm 31 supports the boat 21 with the standby table 33 and the heat treatment stage 4. It is configured to transfer to and from the cap 19. A cooling table 34 is installed on the cooling stage 6, and the second arm 32 is configured to transfer the boat 21 between the cooling table 34 and the cap 19 of the heat treatment stage 4.
[0020]
As shown in FIG. 1, the clean unit 3 that supplies clean air 35 into the housing 2 is configured to blow the clean air 35 toward the standby stage 5 and the cooling stage 6. That is, as shown in FIG. 8, the clean unit 3 includes a suction duct 36 that sucks clean air 35, and a suction fan 37 is installed at the lower end of the suction duct 36. A blowout duct 38 is extended long on the discharge port side of the suction fan 37 so as to extend in the front-rear direction. Air outlets 39, 39 for blowing 35 toward the standby stage 5 and the cooling stage 6 are widely opened.
[0021]
On the other hand, as shown in FIG. 1, an exhaust fan 40 is installed at the rear right corner inside the housing 2, and the exhaust fan 40 is connected to the air outlets 39, 39 of the clean unit 3. The blown clean air 35 is sucked and discharged outside the housing 2.
[0022]
As shown in FIGS. 1 to 4, a wafer transfer device 41 configured by a SCARA robot is installed on the wafer loading stage 7, and the wafer transfer device 41 transfers the wafer W to the pod stage 8. It is configured to transfer between the standby stage 5 and transfer between the pod and the boat 21.
[0023]
That is, as shown in FIG. 9, the wafer transfer device 41 includes a base 42, and a turntable 43 that rotates with respect to the base 42 is installed on the upper surface of the base 42. A linear guide 44 is installed on the turntable 43, and the linear guide 44 is configured to horizontally move a moving table 45 installed thereon. A mounting table 46 is installed on the moving table 45 so as to be moved horizontally by the moving table 45. The mounting table 46 has a plurality of tweezers 47 for supporting the wafer W from below (in the present embodiment). 5), arranged at equal intervals and mounted horizontally. As shown in FIGS. 1 to 4, the wafer transfer device 41 is moved up and down by an elevator 48 constituted by a feed screw mechanism.
[0024]
On the pod stage 8, FOUP (front opning unified pod, hereinafter referred to as a pod) 50 as a carrier (storage container) for carrying the wafer W is placed one by one. The pod 50 is formed in a substantially cubic box shape with one surface opened, and a door 51 is detachably attached to the opening. When a pod is used as a wafer carrier, the wafer is transported in a sealed state, so that the cleanliness of the wafer can be maintained even if particles are present in the surrounding atmosphere. it can. Therefore, it is not necessary to set the cleanliness in the clean room in which the diffusion CVD apparatus is installed, so that the cost required for the clean room can be reduced. Therefore, in the diffusion CVD apparatus according to the present embodiment, the pod 50 is used as a wafer carrier. The pod stage 8 is provided with a door opening / closing device (not shown) for opening and closing the door 51 of the pod 50.
[0025]
FIG. 10 is a block diagram showing a control system of the diffusion CVD apparatus. The control system 60 shown in FIG. 10 is composed of a main controller constructed by a computer and a plurality of sub-controllers. The sub-controller includes a temperature control sub-controller 61 that controls the temperature of the processing chamber, a pressure control sub-controller 62 that controls the pressure of the processing chamber, and a gas control sub-control that controls the gas flow rate of source gas, carrier gas, purge gas, and the like. A controller 63 and a machine control sub-controller 64 for controlling machines such as various elevators, boat transfer devices, and wafer transfer devices are constructed. These sub-controllers are connected to the main controller 66 by a control network 65. .
[0026]
A console (control console) 67 as a display means and input means (user interface) and a storage device 68 for storing recipes and the like are connected to the main controller 66. The console 67 includes a display, a keyboard, and a mouse. The console 67 is configured to display recipe contents (item names, numerical values of control parameters, and the like) on the display, and to transmit operator commands using the keyboard and mouse. .
[0027]
In the present embodiment, a wafer charge (transfer) start time calculation unit 70 is constructed (programmed) in the main controller 66, and the wafer charge start time calculation unit 70 uses a wafer charge transfer start time calculation method described later. Is configured to run.
[0028]
Hereinafter, a diffusion CVD processing method according to an embodiment of the present invention using the diffusion CVD apparatus according to the above configuration will be described with reference to a time chart shown in FIG. To do. In FIG. 11, K1 to K11 indicate steps described later, and t ₁ ~ T ₁₁ Indicates respective required times of the respective steps K1 to K11.
[0029]
The following diffusion CVD processing method is performed by a control sequence for executing a recipe of a film formation process designated in advance. The designated recipe is expanded from the storage device 68 to the RAM of the main controller 66, and the like. This is implemented by commanding the sub-controllers 62-64.
[0030]
First, in the wafer charging process of the first boat shown by K1 in FIG. 11, the wafer W accommodated in the pod 50 is referred to as one of the pair of boats 21, 21 (hereinafter referred to as the first boat 21A). ) Is transferred (charged) by the wafer transfer device 41. Time t required for wafer charging process K1 ₁ Is about 12 minutes when the number of wafer charges is 150.
[0031]
In the wafer charging step K1, as shown in FIG. 1, the pod 50 containing a plurality of wafers W is supplied to the pod stage 8, and is supplied to the pod stage 8 as shown in FIG. The pod 50 thus opened has its door 51 opened by a door opening / closing device. On the other hand, as shown in FIGS. 1 and 2, the first boat 21A is placed on the standby stage 33 of the standby stage 5, and is in a state of waiting for the execution of the wafer charging step K1.
[0032]
Then, in FIG. 9, from the state shown in (a), as shown in (b), the moving base 45 and the mounting base 46 are moved in the direction of the pod 50, and the tweezer 47 is inserted into the pod 50. The wafer W in the pod 50 is received. Subsequently, the tweezer 47 moves back to the position shown in (a). Next, the turntable 43 is reversed, the moving table 45 and the mounting table 46 are moved in the direction of the standby stage 5, and the wafer W held by the tweezer 47 is transferred to the holding groove 25 of the first boat 21A. The wafer transfer device 41 that transferred the wafer W to the first boat 21A reverses the moving table 45 and the mounting table 46 once and then reverses again, and the tweezer 47 is directed to the pod 50 side of FIG. 9A. It becomes a state.
[0033]
At this time, since the wafer transfer device 41 includes the five tweezers 47, the five wafers W are transferred from the five holding grooves of the pod 50 to the five steps of the first boat 21A by one transfer operation. It can be transferred to the holding groove 25. Here, the number of wafers W processed in batch by the first boat 21A (150 in the present embodiment) is larger than the number of wafers W stored in one pod 50 (also 25). The wafer transfer device 41 transfers a predetermined number of wafers W from the plurality of pods 50 to the first boat 21A by being lifted and lowered by the elevator 48.
[0034]
Next, a boat transfer process indicated by K2 in FIG. 11 is performed. Required time t for boat transfer process K2 ₂ Is about 0.5 minutes.
[0035]
In the boat transfer process K2, the first boat 21A on which the designated number of wafers W are transferred on the standby stage 5 is transferred from the standby stage 5 to the heat treatment stage 4 by the first arm 31 of the boat transfer device 30 as shown in FIG. And is transferred onto the cap 19. That is, the first arm 31 is inserted into the outside of the support 27 of the first boat 21A and engaged with the engaging portion 28 of the heat insulating cap portion 26 from below to support the first boat 21A vertically. By turning 90 degrees, the first boat 21A is transferred from the standby stage 5 to the heat treatment stage 4 and transferred onto the cap 19. Then, the first arm 31 that has transferred the first boat 21 </ b> A to the cap 19 returns to the standby stage 5.
[0036]
Next, a boat carrying-in process indicated by K3 in FIG. 11 is performed. Required time t for boat loading process K3 _Three Is about 2 minutes.
[0037]
In the boat carrying-in process K3, as shown in FIG. 5, the first boat 21A supported vertically by the cap 19 is lifted by the elevator 20 and carried into the processing chamber 12 of the process tube 11. When the first boat 21A reaches the upper limit, the outer peripheral portion of the upper surface of the cap 19 is seated on the lower surface of the manifold 14 with the seal ring 15 interposed therebetween, and the lower end opening of the manifold 14 is closed in a sealed state. The chamber 12 is airtightly closed.
[0038]
When the processing chamber 12 is hermetically closed by the cap 19, a temperature increase / temperature stabilization process indicated by K4 in FIG. 11 is performed. That is, the processing chamber 12 is evacuated to a predetermined degree of vacuum by the exhaust pipe 16 and is uniformly heated by the heater unit 18 at a predetermined processing temperature (for example, 800 to 1000 ° C.).
[0039]
When the temperature of the processing chamber 12 is stabilized, a film forming process indicated by K5 in FIG. 11 is performed. That is, in the film forming step K5, a processing gas is supplied to the processing chamber 12 through the gas introduction pipe 17 at a predetermined flow rate. Thereby, a predetermined film forming process is performed.
[0040]
When the predetermined film forming process is completed, nitrogen (N ₂ ) A gas purge step is performed. That is, in the nitrogen gas purge step K6, the nitrogen gas flows through the gas introduction pipe 17 at a predetermined flow rate and time (t ₆ ), The processing chamber 12 is replaced with nitrogen gas and the temperature is lowered.
[0041]
Depending on the type of film to be handled, the required time (t _Four + T _Five + T ₆ ) Is about 1 to 2 hours. That is, for any film type, the time required for the temperature rise / temperature stabilization process K4, the film formation process K5, and the nitrogen gas purge process K6 (t _Four + T _Five + T ₆ ) Is the time t required for the wafer charging process K1. ₁ Compared to about 12 minutes, it takes a long time.
[0042]
During the heat treatment of the first boat 21A, the other boat (hereinafter referred to as the second boat 21B) of the pair of boats 21 and 21 is transferred onto the standby stage 33 of the standby stage 5 and is in a standby state. It has become.
[0043]
Thereafter, a boat unloading process indicated by K7 in FIG. 11 is performed. Required time t for boat unloading process K7 ₇ Is about 2 minutes.
[0044]
That is, in the boat unloading step K7, as shown in FIG. 6, the cap 19 supporting the first boat 21A is lowered by the elevator 20, and the first boat 21A is unloaded from the processing chamber 12 of the process tube 11. Is done. The furnace port 13 of the process chamber 12 of the process tube 11 from which the first boat 21A has been unloaded is closed by a shutter (not shown), thereby preventing the high temperature atmosphere in the process chamber 12 from escaping. The first boat 21A (including the held wafer W group) unloaded from the processing chamber 12 is in a high temperature state.
[0045]
Subsequently, a boat transfer process indicated by K8 in FIG. 11 is performed, and the first boat 21A in a high temperature state is transferred from the heat treatment stage 4 to the cooling stage 6. Required time t of boat transfer process K8 ₈ Is about 0.5 minutes.
[0046]
That is, as shown in FIG. 3, the high-temperature processed first boat 21 </ b> A unloaded from the processing chamber 12 is transferred from the heat treatment stage 4 on the axis of the process tube 11 to the cooling stage 6. The second arm 32 is immediately transferred and temporarily placed. At this time, the second arm 32 is inserted into the outside of the post 27 of the processed first boat 21A and engaged with the engaging portion 28 of the heat insulating cap portion 26 from below to vertically move the processed first boat 21A. In this state, the processed first boat 21A is transferred from the cap 19 of the heat treatment stage 4 onto the cooling table 34 of the cooling stage 6 and mounted thereon.
[0047]
The high-temperature processed first boat 21A transferred to the cooling stage 34 of the cooling stage 6 is subjected to a cooling process indicated by K9 in FIG. Time required t for the cooling process K9 ₉ Is about 10 minutes.
[0048]
In the cooling step K9, as shown in FIG. 4, since the cooling stage 6 is set in the vicinity of the clean air outlet 39 of the clean unit 3, the high temperature transferred to the cooling stage 34 of the cooling stage 6 is set. The first boat 21 </ b> A in the state is cooled very effectively by the clean air 35 blown out from the air outlet 39 of the clean unit 3. At this time, as shown in FIG. 4, the flow of the clean air 35 blown out from the air outlet 39 of the clean unit 3 is the rear part of the housing 2 that is opposite to the standby stage 5 when viewed from the air outlet 39. Since it goes to the exhaust fan 40 arranged in the right corner, it does not go in the direction of the heat treatment stage 4 and the standby stage 5. Accordingly, the clean air 35 that has contacted the processed first boat 21 </ b> A flows into the heat treatment stage 4 and the standby stage 5, thereby contaminating the wafer W group held on the second boat 21 </ b> B of the heat treatment stage 4 and the standby stage 5. That can be prevented.
[0049]
Thereafter, the first boat 21A of the cooling table 34 is subjected to a boat transfer process indicated by K10 in FIG. Required time t of boat transfer process K10 ₇ Is about 0.5 minutes. The boat transfer process K10 is performed as follows. At this time, the processed first boat 21A is sufficiently cooled to, for example, 150 ° C. or lower.
[0050]
That is, the second arm 32 of the boat transfer device 30 is inserted outside the support 27 of the first boat 21A and engaged with the engaging portion 28 of the heat insulating cap portion 26 from below to vertically support the first boat 21A. In this state, the first boat 21A is transferred from the cooling stage 6 to the heat treatment stage 4 by rotating about 90 degrees. When the first boat 21A is transferred to the heat treatment stage 4, the first arm 31 of the boat transfer device 30 is rotated about 90 degrees and moved to the heat treatment stage 4, and the first boat 21A of the heat treatment stage 4 is received. When the first boat 21A is received, the first arm 31 reversely rotates about 90 degrees in the original direction, transfers the first boat 21A from the heat treatment stage 4 to the standby stage 5, and transfers it to the standby table 33. In the state of being transferred to the standby table 33, the three holding members 24 of the first boat 21A are in a state where the wafer transfer device 41 side is opened.
[0051]
Next, the discharge process indicated by K11 in FIG. Time required t for the discharge process K11 ₁₁ Is about 12 minutes. The discharge process K11 is performed by the operation of the wafer transfer device 41 in accordance with the operation described above with reference to FIG.
[0052]
That is, the wafer transfer device 41 receives the processed wafer W from the first boat 21 A of the standby stage 5 and transfers it to the pod 50 of the pod stage 8. At this time, since the number of processed wafers W batch-processed by the first boat 21 </ b> A is larger than the number of wafers W stored in one pod 50, the wafer transfer device 41 is lifted and lowered by the elevator 48, A predetermined number of wafers W are stored in a plurality of pods 50 that are replaced with the stage 8.
[0053]
When all the processed wafers W are returned to the pod 50, a new wafer W to be processed next is transferred (charged) to the first boat 21A on the stand 33 by the wafer transfer device 41. The going wafer charge process K1 is executed. However, in the diffusion CVD processing method according to the present embodiment, the wafer charge process K1 is started at the timing calculated by the wafer charge start time calculation method described later. The same applies to the second boat 21B.
[0054]
Thereafter, the above-described operation is alternately repeated between the first boat 21A and the second boat 21B, whereby a large number of wafers W are batch processed by the diffusion CVD apparatus 1.
[0055]
By the way, in the case of the conventional example in which the wafer charging process K1 is subsequently performed after the completion of the discharging process K11, the wafer is transferred to one boat (the first boat or the second boat) in which the wafer charging process K1 is performed. The new wafer group waits in the standby stage 5 in the atmospheric atmosphere for a long period of about 1 to 2 hours until the processing of the other boat (first boat or second boat) in the heat treatment stage 4 is completed. . Thus, when a new wafer group is exposed to the air atmosphere for a long time, a natural oxide film is formed on the surface of the wafer W to be processed by oxygen and moisture in the air.
[0056]
Therefore, in the present embodiment, the optimum value at the start time of the wafer charge process K1 is obtained by the wafer charge start time calculation method, and the wafer charge process K1 is started at the calculated timing, whereby the standby stage 5 in the atmospheric atmosphere. It is assumed that the waiting time is shortened the most.
[0057]
Next, a wafer charge start time calculation method according to the present embodiment will be described with reference to FIG. The flow shown in FIG. 12 is executed by the wafer charge start time calculation unit 70 of the main controller 66.
[0058]
In the first step indicated by S1 in FIG. 12, the accumulated time until the boat unloading process K7 of the first boat is calculated. That is, if the cumulative time is T, the cumulative time is T = t ₁ + T ₂ + T _Three + T _Four + T _Five + T ₆ + T ₇ Sought by. T ₁ ~ T ₇ Is the time required for each of the steps K1 to K7.
[0059]
Next, in the second step indicated by S2 in FIG. 12, it is determined whether or not "the accumulated time until the boat unloading process K7 of the first boat". If it is not the accumulated time (NO), the process returns to the first step S1, and the first step S1 and the second step S2 are repeated. If it is the accumulated time (YES), the process proceeds to the third step S3.
[0060]
In the third step S3, the wafer charging start time T ′ of the second boat is calculated. That is, the wafer charge start time T ′ is T ′ = T−t. ₁ Sought by.
[0061]
Based on the wafer charge start time calculated as described above, the main controller 66 executes the flow shown in FIG.
[0062]
That is, in the first step P1 shown in FIG. 13, it is determined whether or not “the recipe execution time has reached the start time of wafer charge to the second boat”. When it is not the start time (NO), the first step P1 is repeated, and when it is the start time (YES), the process proceeds to the second step P2.
[0063]
In the second step P2, the wafer charging process K1 for the second boat is started. In the above description, the case where the start time of the wafer charging process K1 for the second boat is calculated and executed has been described. However, since the first boat and the second boat are operated in the same manner, A boat is similarly calculated and executed.
[0064]
According to the present embodiment, the optimum value at the time of starting the wafer charge is obtained in advance, and the waiting time of the wafer waiting for the next processing is shortened to the minimum, thereby minimizing the time that the wafer is exposed to the air atmosphere. Since it can suppress, the increase of the natural oxide film formed on the surface of a wafer can be suppressed.
[0065]
For example, the required time t of the wafer charging process K1 ₁ Is about 12 minutes for 150 wafers, and the required time t for boat unloading process K7 ₇ And required time t of boat transfer process K8 ₈ Total time t with ₇ + T ₈ Is about 4 minutes, required time t for boat transfer process K2. ₂ Is 0.5 minutes, the time during which the waiting wafer W is exposed to the air atmosphere is about 16.5 minutes.
[0066]
Here, FIG. 14 is a graph showing the increase characteristic of the natural oxide film on the surface of the wafer exposed to the air atmosphere. According to FIG. 14, the thickness of the natural oxide film in about 16.5 minutes is 1 mm or less. A natural oxide film of this level does not affect the variation in the film thickness processed on the wafer or increase the contact resistance, so IC integration, quality (accuracy, etc.) and performance An adverse effect on (computation speed, etc.) and reliability can be prevented in advance.
[0067]
Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.
[0068]
For example, the completion of the wafer charging process to the second boat is not limited to be set to be completed before the first boat unloading process, but to the second boat immediately before completing the boat transfer process of the first boat. You may set so that a wafer charge process may be complete | finished. In this case, since the time for which the wafer is exposed to the air atmosphere can be further shortened, an increase in the natural oxide film can be further reduced.
[0069]
The gas supplied to the housing is not limited to clean air, and may be an inert gas such as nitrogen gas.
[0070]
The diffusion CVD apparatus can be used for heat treatments such as annealing, oxide film formation, diffusion, and film formation.
[0071]
In this embodiment, the case of using a batch type vertical hot wall type diffusion CVD apparatus has been described. However, the present invention is not limited to this, and is applicable to all substrate processing methods such as a batch type horizontal hot wall type diffusion CVD apparatus. Can do.
[0072]
In the above embodiment, the case where the wafer is subjected to the heat treatment has been described. However, the substrate to be processed may be a photomask, a printed wiring board, a liquid crystal panel, a compact disk, a magnetic disk, or the like.
[0073]
【The invention's effect】
As described above, according to the present invention, the time during which the wafer is exposed to the air atmosphere can be shortened.
[Brief description of the drawings]
FIG. 1 is a plan sectional view showing a diffusion CVD apparatus used in a diffusion CVD processing method according to an embodiment of the present invention.
FIG. 2 is a perspective view thereof.
FIG. 3 is a perspective view showing that a processed boat is being cooled.
FIG. 4 is a plan sectional view of the same.
FIG. 5 is a longitudinal sectional view showing the heat treatment stage during processing.
FIG. 6 is a longitudinal sectional view showing the same after the boat is carried out.
FIG. 7 is a perspective view showing a boat transfer device.
FIG. 8 is a perspective view showing a clean unit.
FIGS. 9A and 9B are side views showing the wafer transfer apparatus, wherein FIG. 9A shows a shortened state and FIG. 9B shows an extended state.
FIG. 10 is a block diagram showing a control system.
FIG. 11 is a time chart showing a diffusion CVD processing method.
FIG. 12 is a flowchart showing a method for calculating a wafer charge start time.
FIG. 13 is a flowchart showing an execution flow at the start of wafer charging.
FIG. 14 is a graph showing an increase characteristic of a natural oxide film on the surface of a wafer exposed to an air atmosphere.
[Explanation of symbols]
W: Wafer (substrate), 1 ... Diffusion CVD apparatus (substrate processing apparatus), 2 ... Housing, 3 ... Clean unit, 4 ... Heat treatment stage, 5 ... Standby stage, 6 ... Cooling stage, 7 ... Wafer loading stage, 8 Pod stage, 9 notch aligner, 11 process tube, 12 processing chamber, 13 furnace opening, 14 manifold, 15 seal ring, 16 exhaust pipe, 17 gas introduction pipe, 18 heater unit, DESCRIPTION OF SYMBOLS 19 ... Cap, 20 ... Elevator, 21 ... Boat, 21A ... First boat, 21B ... Second boat, 22 ... Upper end plate, 23 ... Lower end plate, 24 ... Holding member, 25 ... Holding groove, 26 ... Thermal insulation Cap part, 27 ... support, 28 ... engagement part, 29 ... base, 30 ... boat transfer device, 31 ... first arm, 32 ... second arm, 33 ... standby stand, 34 ... cooling stand, 35 ... Lean air, 36 ... suction duct, 37 ... suction fan, 38 ... blowout duct, 39 ... blower outlet, 40 ... exhaust fan, 41 ... wafer transfer device, 42 ... base, 43 ... turntable, 44 ... linear guide, 45 ... Moving platform, 46 ... Mounting platform, 47 ... Tweezer, 48 ... Elevator, 50 ... Pod, 51 ... Door, 60 ... Control system, 61 ... Temperature control sub-controller, 62 ... Pressure control sub-controller, 63 ... Gas control sub-controller 64 ... Machine control sub-controller, 65 ... Control network, 66 ... Main controller, 67 ... Console (control console), 68 ... Storage device, 70 ... Wafer charge start time calculation unit.

Claims (2)

A process tube in which a processing chamber is formed; a boat that enters and exits the processing chamber to load and unload a plurality of substrates; and a substrate transfer device that transfers the plurality of substrates to and from the boat outside the processing chamber. And a stage for temporarily placing the boat outside the processing chamber, in a method for manufacturing a semiconductor device in which at least two boats are used sequentially,
The substrate by the substrate transfer apparatus to another boat processed next to the boat immediately before the step of transferring the boat carried out of the processing chamber to the stage after the processing in the processing chamber is completed is completed. A method of manufacturing a semiconductor device, wherein the transfer step is set to be completed . A process tube forming a processing chamber; at least two boats that enter and exit the processing chamber to load and unload a plurality of substrates; and transfer the plurality of substrates to the boat outside the processing chamber. A substrate transfer device, a stage for temporarily placing the boat outside the processing chamber, and immediately before the completion of the processing in the processing chamber and the step of transferring the boat unloaded from the processing chamber to the stage a substrate processing apparatus and a control system for setting to terminate the transfer step of the substrate by the substrate transfer device to another baud bets that will be processed next of the boat.

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