JP2003100736A - Substrate treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate organic matters, impurities or the like adsorbed on a wafer surface, prior to treatment. SOLUTION: In a vertical oxidation apparatus, having a process tube 15 where plural wafers W are treated being supported by a boat 19, a waiting chamber 3 where a load lock chamber structure is formed directly under the process tube 15 and the boat 19 waits and a wafer moving an putting chamber 25, where the waiting chamber 3 is formed adjacent and a wafer-moving and mounting device 30 is set up, plural heaters 40 for heating the wafer W group prior to the treatment are arranged with equal intervals radially around the boat 19 in the waiting chamber 3 and each of the wafers is erected vertically each. Because substances, such as organic matters, impurities or the like adsorbed on the wafer surface can be eliminated in advance by heating the wafer group, in the waiting chamber by the heaters prior to delivering to the process tube, entering of the strange substances adsorbed on the wafers can be reduced and quality and reliability of the treatment can be enhanced.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus, and more particularly to a technique for removing organic substances and impurities from a substrate to be processed, for example, a semiconductor integrated circuit including a semiconductor element. The present invention relates to a semiconductor wafer which is effective for oxidizing a semiconductor wafer (hereinafter, referred to as a wafer) in which impurities are formed, diffusing impurities, and forming a CVD film such as an insulating film or a metal film. 2. Description of the Related Art Semiconductor integrated circuits (hereinafter referred to as ICs).
In the manufacturing method, a vertical oxidation apparatus is used to oxidize a wafer. As a conventional vertical oxidizing apparatus, a process tube for processing a plurality of wafers held by a boat, a heater unit laid outside the process tube to heat a processing chamber of the process tube, and a large under the process tube. A standby chamber constructed in a load lock chamber structure that can withstand a pressure lower than the atmospheric pressure, and a plurality of wafers are loaded (discharged) from the outside of the standby chamber with a plurality of wafers loaded in a standby boat in the standby chamber. )). In this vertical oxidation apparatus, when a wafer is loaded into a boat by a wafer transfer device, the standby chamber is evacuated to adjust the pressure in the standby chamber to be equal to the pressure in the processing chamber of the process tube. . Thereafter, the boat is carried into the processing chamber of the process tube (boat loading), and a plurality of wafers held by the boat in the processing chamber are oxidized by being heated by the heater unit. As described above, by removing air and moisture by exhausting the standby chamber before the wafer is loaded into the processing chamber, air and moisture from the standby chamber to the processing chamber when the boat is loaded into the processing chamber can be obtained. In this vertical oxidizing apparatus, the quality and reliability of the oxidizing treatment can be improved. [0004] However, in the above-described vertical oxidation apparatus, foreign substances such as organic substances and impurities adsorbed on the surface of the wafer cannot be removed.
There is a problem in that foreign substances such as organic substances and impurities that have entered the processing chamber while being adsorbed on the surface of the wafer are taken into the oxide film, thereby adversely affecting the film quality. An object of the present invention is to provide a substrate processing apparatus capable of preventing foreign substances adsorbed on a substrate surface from entering a processing chamber. A substrate processing apparatus according to the present invention has a processing chamber for processing a plurality of substrates in a state of being held by a boat, and has the boat stand by adjacent to the processing chamber. A closed chamber; and a heater installed in the closed chamber and heating the plurality of substrates held by the boat before processing. According to the above-described means, the substrate held by the boat is heated by the heater in the closed chamber before the processing, so that foreign substances such as organic substances and impurities adsorbed on the surface of the substrate are liquefied and vaporized. Since it is possible to remove, it is possible to reduce the intrusion of foreign matter adsorbed on the substrate into the processing chamber. An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, a substrate processing apparatus according to the present invention is configured as a vertical oxidizing apparatus for oxidizing a wafer in an IC manufacturing method. In the vertical oxidation apparatus 1 according to the present embodiment, a FOUP (frontopening unified pod) is used as a carrier for transporting wafers.
Hereinafter, it is called a pod. ) Is used. In the following description, front, rear, left and right are based on FIG. That is, the case 2 side is the front side, the opposite side, that is, the case 4 side of the load lock chamber structure is the rear side, the clean air unit 37 side is the left side, and the opposite side, that is, the elevator 36 side of the wafer transfer device 30 is the right side. As shown in FIG. 1, the vertical oxidizing apparatus 1 has a housing 2, and a boat 19 is provided on the rear side of the housing 2.
A housing 4 (hereinafter, referred to as a pressure-resistant housing) having a load lock chamber structure in which a standby chamber 3 in which the device stands by is provided. The standby chamber 3 is configured as a closed chamber having airtightness capable of maintaining a pressure lower than the atmospheric pressure, and the pressure-resistant housing 4 is formed in a substantially rectangular parallelepiped box shape having a volume capable of storing the boat 19. A wafer loading / unloading port 5 opened and closed by a gate 6 is opened on a front wall of the pressure-resistant housing 4. An exhaust pipe 7 for exhausting the standby chamber 3 to a pressure lower than the atmospheric pressure and an air supply pipe 8 for supplying nitrogen (N ₂ ) gas to the standby chamber 3 are connected to the left and right side walls of the pressure-resistant housing 4. Have been. As shown in FIG. 2, a boat loading / unloading port 11 is opened on the ceiling wall of the pressure-resistant housing 4, and the boat loading / unloading port 11 is opened and closed by a shutter 12. . A heater unit 13 is installed vertically on the pressure-resistant housing 4.
Inside the process tube 15 forming the processing chamber 14
Is arranged. The process tube 15 is formed in a cylindrical shape having a closed upper end and an open lower end, and is arranged concentrically with the heater unit 13. A hollow cylindrical portion of the process tube 15 forms a processing chamber 14. The process tube 15 is supported on a ceiling wall of the pressure-resistant housing 4 via a manifold 16, and a raw material gas, a purge gas, and the like are introduced into the manifold 16 into a processing chamber 14 formed by a hollow cylindrical portion of the process tube 15. And an exhaust pipe 18 for exhausting the inside of the process tube 15 are connected to each other. The manifold 16 is arranged concentrically with the boat loading / unloading port 11 of the pressure-resistant housing 4. At the center of the rear wall of the waiting room 3, a boat elevator 20 for raising and lowering the boat 19 is installed. The boat elevator 20 includes a guide rail, a feed screw shaft, an electric motor, and the like. The seal cap 22 is horizontally supported by an arm 21 to be moved up and down. The seal cap 22 is configured to seal the boat loading / unloading port 11 of the pressure-resistant housing 4 serving as a furnace port of the process tube 15 and to vertically support the boat 19. A rotary shaft 24 driven by a rotary actuator 23 is inserted through the center line of the seal cap 22, and the upper end of the rotary shaft 24 is configured to support the boat 19 vertically from directly below. A plurality of boats 19 (for example, 25, 50, 100, 125, 15
In such a state that wafers W (eg, 0 wafers) are horizontally supported with their centers aligned, the loading and unloading of the seal cap 22 by the boat elevator 20 with respect to the processing chamber of the process tube 15 is performed. I have. As shown in FIGS. 1 and 2, the housing 2 forms a wafer transfer chamber 25, and a wafer W is placed on the front wall of the housing 2 with respect to the wafer transfer chamber 25. A wafer loading / unloading port 26 for loading / unloading is provided. A wafer transfer device 30 for transferring the wafer W is installed inside the wafer transfer chamber 25. The wafer transfer device 30 includes a rotary actuator 31, and the rotary actuator 31 is configured to rotate a first linear actuator 32 installed on an upper surface in a horizontal plane. A second linear actuator 33 is provided on an upper surface of the first linear actuator 32, and the first linear actuator 32 is configured to horizontally move the second linear actuator 33. A movable table 34 is provided on the upper surface of the second linear actuator 33, and the second linear actuator 33 is configured to horizontally move the movable table 34. A plurality of (five in this embodiment) tweezers 35 for supporting the wafer W from below are horizontally mounted on the movable table 34 at equal intervals. The wafer transfer device 30 is moved up and down by an elevator 36 constituted by a feed screw device or the like. On the opposite side of the elevator 36, the housing 2
Is provided with a clean air unit 37 for supplying clean air. As shown in FIGS. 1 and 2, a pod opener 38 is installed at the wafer loading / unloading port 26 opened on the front wall of the housing 2. Pod opener 3
Reference numeral 8 denotes a mounting table 38a on which the pod P is mounted, and a mounting table 38a.
And a cap attaching / detaching mechanism 38b for attaching / detaching a cap of the pod P placed on the mounting table 38a. The mouth is opened and closed. The pod P is supplied to and discharged from the mounting table 38a of the pod opener 38 by an in-process transfer device (RGV) (not shown). Further, as shown in FIGS. 1 and 2, the standby chamber 3 is provided with a plurality of heaters 40 for removing foreign substances such as organic substances and impurities (in this embodiment,
And eight heaters 40 are arranged at equal intervals in the circumferential direction on a concentric circle surrounding the seal cap 22.
9 and is vertically installed so as to be parallel to the center line of the ninth. However, a pair of heaters 40, 40 located on the wafer loading / unloading port 5 side of the standby chamber 3 are connected to the wafer transfer device 3.
0 so as not to hinder the loading and unloading operations of the wafer W by the wafer W. Heater 4
Reference numeral 0 denotes a base 41 which is formed in a cylindrical shape and is vertically installed, and a heating element 4 which is vertically installed on an upper surface of the base 41.
2 and a heating element 42 which is vertically provided on the upper surface of the base 41 and
And a reflection plate 43 for reflecting the heat rays of the direction of the boat 19 in the direction of the boat 19. Bases 41 of the pair of heaters 40, 40 located on the side of the wafer loading / unloading port 5 include a pair of linear actuators 44 laid on the bottom surface of the standby chamber 3 in the left-right direction.
Each of the linear actuators 44, 44 is reciprocally moved in the left-right direction. Hereinafter, a wafer oxidation step in a method of manufacturing an IC using the vertical oxidation apparatus according to the above configuration will be described. From now on, a plurality of wafers W to be oxidized are transported by the in-process transport device to the vertical oxidizing device 1 for performing the oxidizing process in a state where a plurality of wafers W are stored in the pod P. As shown in FIGS. 1 and 2, the transported pod P is delivered from the in-process transport device and placed on the loading table 38 a of the pod opener 38. The cap of the pod P is removed by the cap attaching / detaching mechanism 38b,
The wafer entrance of the pod P is opened. When the pod P is opened by the pod opener 38, five wafers W from the pod P are transferred by the tweezers 35 of the wafer transfer device 30 to the wafer loading / unloading port 26.
And is carried into the wafer transfer chamber 25 through the wafer carry-in / out port 26. When the five wafers W are loaded into the wafer transfer chamber 25 by the wafer transfer device 30, the wafer transfer port 5 of the pressure-resistant housing 4 is opened by the gate 6. Tweezer 35 of wafer transfer device 30
The five wafers W held by the above are loaded (charged) into the boat 19 through the wafer loading / unloading port 5 by the wafer transfer device 30. At the time of loading the wafer W into the boat 19 by the wafer transfer device 30, a pair of heaters 40, 40 located on the wafer loading / unloading port 5 side of the standby chamber 3 as shown in FIG. Are both linear actuators 44, 4
By being moved outward in the left-right direction by 4, they are in an open state with each other. By the opening operation of the heaters 40, the loading operation of the wafer W by the wafer transfer device 30 is prevented from being hindered by the heater 40. Thereafter, the boat 19 is moved from the pod P of the wafer W to the boat 19.
The loading operation by the wafer transfer device 30 is repeated. During this time, the boat loading / unloading port 11 is closed by the shutter 12, thereby preventing the high-temperature atmosphere of the process tube 15 from flowing into the standby chamber 3.
For this reason, the wafer W being loaded and the loaded wafer W are not exposed to the high-temperature atmosphere, and the exposure of the wafer W to the high-temperature atmosphere can be prevented from causing adverse effects such as natural oxidation. As shown in FIGS. 1 and 2, when a predetermined number of wafers W are loaded into the boat 19, the wafer loading / unloading port 5 is closed by the gate 6. Next, while the standby chamber 3 is evacuated by the exhaust pipe 7 and the boat 19 is rotated by the rotary actuator 23, the boat 19 and the wafers W held by the boat 19 are heated from the surroundings by eight heaters 40. At this time, the pair of heaters 40, 40 located on the side of the wafer loading / unloading port 5 are connected to the linear actuators 44, 4.
By being moved inward in the left-right direction by 4 to perform the closing operation, the heaters 40 are returned to the positions at equal intervals in the circumferential direction together with the other six heaters 40. When the wafer W is heated by the heater 40, foreign substances such as organic substances and impurities adsorbed on the surface of the wafer W are removed by the action of liquefaction or vaporization by heating.
At this time, since the standby chamber 3 is evacuated to vacuum, effects such as liquefaction and vaporization by heating are effectively caused. Since the heater 40 extends in a direction parallel to the center line of the boat 19, the group of wafers W held in alignment with the longitudinal direction of the boat 19 is uniformly heated over the entire length. Further, since eight heaters 40 are arranged at equal intervals in the circumferential direction and the boat 19 is rotated, the surface of the wafer W held concentrically on the boat 19 is uniformly heated in the circumferential direction. Is done. Therefore, the foreign matter adsorbed on the surface of the wafer W is uniformly removed over the entire length of the boat 19 and the surface of the wafer W, so that the foreign matter is uniformly removed over the entire length of the wafer group and the wafer surface. Incidentally, the heating temperature and time of the heater 40 for removing foreign matters such as organic substances and impurities adsorbed on the surface of the wafer W, the heating rate, the distance between the heater 40 and the boat 19, and the pressure of the standby chamber 3 Conditions such as the number of wafers to be processed, the size of the cleaning, the degree of cleaning, and the oxidation process are determined by experiments and computer simulations and empirical methods based on past results. It is desirable to set appropriately according to processing conditions such as types. After a predetermined time required for removing foreign matter by heating the heater 40, nitrogen gas is supplied to the standby chamber 3 through the air supply pipe 8, and the standby chamber 3 is purged with nitrogen gas. 3, foreign substances such as oxygen and moisture in the atmosphere, organic substances and impurities desorbed from the surface of the wafer W, and the residue obtained by liquefying or vaporizing the foreign substances are removed. The standby chamber 3 is purged with nitrogen gas.
Is adjusted to be equal to the pressure preset in the processing chamber 14 of the process tube 15, the boat loading / unloading port 11 is opened by the shutter 12 and supported by the seal cap 22 as shown in FIG. Boat 19
Is lifted by the boat elevator 20 and loaded into the processing chamber 14 of the process tube 15 (boat loading). When the boat 19 reaches the upper limit, the boat 19
Since the peripheral portion of the upper surface of the seal cap 22 supporting the port closes the boat loading / unloading port 11 in a sealed state, the processing chamber 14 of the process tube 15 is airtightly closed. When the boat 19 is carried into the processing chamber 14, oxygen and moisture inside the standby chamber 3 have been removed in advance.
External oxygen and moisture are reliably prevented from entering the processing chamber 14 as the boat 19 is carried into the processing chamber 14. Thereafter, the processing chamber 1 of the process tube 15
4 is exhausted by an exhaust pipe 18 so as to be at a predetermined pressure in a state of being hermetically closed, heated to a predetermined temperature by a heater unit 13, and an oxidant such as oxygen or water vapor is supplied to a predetermined by a gas introduction pipe 17. Only the flow rate is supplied. Thereby, the wafer W is oxidized according to the processing conditions set in advance. Here, foreign matters such as organic substances and impurities adsorbed on the surface of the wafer W are removed in advance in the standby chamber 3 before the boat 19 is carried into the processing chamber 14. Adverse effects of foreign substances such as organic substances and impurities are avoided beforehand. Therefore, the wafer W is subjected to an extremely high quality and highly reliable oxidation process. After a predetermined processing time has elapsed, the boat 19 holding the processed wafer W is moved to the standby chamber 3 by lowering the boat 19 by the boat elevator 20 as shown in FIG. It is carried out (boat unloading). When the boat 19 is carried out to the waiting room 3, the boat entrance 11 is closed by the shutter 12. Next, in a state where the standby chamber 3 is load-locked, the nitrogen gas flows through the air supply pipe 8 and the exhaust pipe 7 to the standby chamber 3 so that the high temperature (for example, 50
The processed wafer W that has reached (0 to 600 ° C.) is forcibly cooled by nitrogen gas, and is cooled to a temperature (for example, 25 to 50 ° C.) that can be stored in the pod P. At this time, by forcibly flowing nitrogen gas as a cooling medium to the standby chamber 3 through the air supply pipe 8 and the exhaust pipe 7, fresh low-temperature nitrogen gas is always brought into contact with the high-temperature wafer W to improve heat exchange efficiency. Since the temperature can be increased, the temperature lowering time of the wafer W can be reduced. When the temperature of the processed wafer W on the boat 19 drops to a predetermined temperature, the wafer loading / unloading port 5 of the standby chamber 3 is opened by the gate 6. Subsequently, the processed wafer W of the cooled boat 19 is removed (discharged) by the wafer transfer device 30, carried into the wafer transfer chamber 25, and emptied on the mounting table 38 a of the pod opener 38. Is stored in the pod P. This wafer transfer device 3
As shown in FIG. 3, the pair of heaters 40, 40 located on the wafer loading / unloading port 5 side of the standby chamber 3 also use the two linear actuators 44, By being moved to the outside in the left-right direction by 44, they are in a state of being opened to each other.
The opening operation of the heaters 40 prevents the heater 40 from obstructing the wafer transfer device 30 from removing the wafer W. When a predetermined number of processed wafers W are stored, the pod P is mounted with a cap by the cap attaching / detaching mechanism 38b of the pod opener 38,
The wafer is transported from a to the next processing step by the in-process transport device. The removal operation and the storage operation in the pod P are repeated for all the processed wafers W in the boat 19. Thereafter, the above-described operation is repeated, and the number of wafers W is, for example, 25, 50, 100, 125, 1
Batch processing is carried out by the vertical oxidizer 1 for every 50 sheets. According to the above embodiment, the following effects can be obtained. 1) By arranging a plurality of heaters for heating a plurality of wafers held in a boat around a seal cap in a standby chamber, heating the wafers held in the boat in the standby chamber by the heaters. Therefore, foreign substances such as organic substances and impurities adsorbed on the surface of the wafer can be removed. 2) The wafer held in the boat in the waiting room is heated by the heater to remove foreign matters such as organic substances and impurities adsorbed on the surface of the wafer before the boat is carried into the processing chamber of the process tube. Accordingly, foreign substances such as organic substances and impurities can be prevented from entering the processing chamber. Therefore, it is possible to prevent oxidization of a wafer in the processing chamber from being adversely affected by foreign substances such as organic substances and impurities. , The quality and reliability of the oxidation treatment can be increased. 3) By laying the heaters in a direction parallel to the center line of the boat, a row of wafers aligned and held in the longitudinal direction of the boat can be uniformly heated over the entire length, so that the surface of the wafer can be heated. The foreign substances adsorbed on the wafer group can be uniformly removed over the entire length of the wafer group. 4) A plurality of heaters are arranged at equal intervals in the circumferential direction around the seal cap in the standby chamber, and the boat is rotated so that the wafer is concentrically held in the plane of the wafer in the circumferential direction. Therefore, foreign matters adsorbed on the surface of the wafer can be uniformly removed over the wafer surface. 5) By loading the heater positioned on the side of the wafer loading / unloading port of the standby chamber so as to be movable in the left / right direction with respect to the wafer loading / unloading port, the wafer transfer apparatus can load the wafer into the boat. In addition, since the heater positioned at the wafer loading / unloading side of the standby chamber can be moved to the evacuation position during the loading / unloading operation, it is possible to prevent the heater from obstructing the loading and unloading of the wafer by the wafer transfer device. Can be prevented. The present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the scope of the present invention. For example, the number of heaters is not limited to eight around the seal cap, and less than eight or more than eight heaters may be provided. Further, the specific structure of the heater is not limited to adopting the structure of the above embodiment. Incidentally, the heating element of the heater may be a resistor or a heating lamp. In the above-described embodiment, the case of the vertical oxidizing apparatus has been described.
The present invention can be applied to all substrate processing apparatuses such as a CVD apparatus and other heat treatment apparatuses. As described above, according to the present invention,
By heating the substrate held by the boat in the closed chamber with a heater before processing, foreign substances such as organic substances and impurities adsorbed on the surface of the substrate can be removed.
Intrusion of foreign matter adsorbed on the substrate into the processing chamber can be reduced, and as a result, processing quality and reliability can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan sectional view showing a vertical oxidizing apparatus according to an embodiment of the present invention. FIG. 2 is a partially omitted side sectional view. FIG. 3 is a plan sectional view showing an operation of loading a wafer into a boat. FIG. 4 is a partially omitted side sectional view showing an oxidation treatment step. [Description of Signs] W: Wafer (substrate), P: Pod (wafer carrier),
DESCRIPTION OF SYMBOLS 1 ... Vertical oxidation apparatus (substrate processing apparatus), 2 ... Case, 3 ... Stand-by room (closed room), 4 ... Pressure-resistant case, 5 ... Wafer carry-in / out port, 6 ... Gate, 7 ... Exhaust pipe, 8 ... Supply Trachea, 11: Boat loading / unloading port, 12: Shutter, 13: Heater unit, 14: Processing chamber, 15: Process tube, 16: Manifold, 17: Gas introduction pipe, 18: Exhaust pipe, 19 ...
Boat, 20 ... boat elevator, 21 ... arm, 22
... seal cap, 23 ... rotary actuator,
24: rotating shaft, 25: wafer transfer chamber (substrate transfer chamber), 2
6: Wafer loading / unloading port, 30: Wafer transfer device, 31:
Rotary actuator, 32: first linear actuator, 33: second linear actuator, 34: moving table, 35: tweezer, 36: elevator, 37: clean air unit, 38: pod opener, 38a: mounting table, 38b: cap removable Mechanism, 40 ... heater, 41 ...
Base, 42: heating element, 43: reflector, 44: linear actuator.

   ────────────────────────────────────────────────── ─── Continuation of front page    F term (reference) 5F031 CA02 DA08 EA14 FA01 FA09                       FA12 GA13 GA47 GA49 HA67                       LA12 MA30 NA02 NA04 NA07                       NA14 NA15 PA23                 5F045 BB14 DP19 DP27 DQ05 EB08                       EB12 EB14 EK06 EK08 EK22                       EN04 EN05

Claims (1)

Claims: 1. A processing chamber for processing a plurality of substrates in a state of being held by a boat, a sealed chamber adjacent to the processing chamber for holding the boat, and a processing chamber installed in the closed chamber. And a heater for heating the plurality of substrates held by the boat before processing.