Patent Application
20110183279
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2010-015600, filed on Jan. 27, 2010, the entire content of which is incorporated herein by reference.
Embodiments described herein relate generally to a substrate heating apparatus and a substrate heating method for heating a substrate of, for example, a flat panel display (FPD) or a solar cell, and a substrate processing system for performing a process including a heat treatment on a substrate.
In manufacturing a substrate of a flat panel display (FPD) or a solar cell, a film forming process that includes heat treatment is generally performed. As a system for efficiently performing such process including heat treatment, a multi-chamber type substrate processing system provided with a plurality of processing units and one or more pre-heating units is known in the prior art (for example, See Japanese Laid-Open Patent Publication No. 11-312727).
In such multi-chamber type substrate processing system, a substrate is heated up to an approximate process temperature in a pre-heating unit and then transferred to each of a plurality of processing units. In this case, the time required for raising the temperature in the pre-heating unit affects productivity such that it is required to raise the temperature as rapidly as possible. To prevent a substrate from being warped, it is further required to uniformly raise the temperature and to stably maintain the temperature when a predetermined temperature is reached.
As a method for rapidly heating and controlling a substrate at a predetermined temperature, the use of a heat source such as a lamp using radiant heat is known. Also, as a heating method, it is known to use heat transmission or heat conduction by mounting a substrate on a mounting table in which a resistance heater is provided as a heat source.
Among these ways of heating, the use of a lamp exploiting radiant heat can instantaneously control heat transmission such that it is possible to rapidly heat up a substrate as well as to maintain a uniform temperature stably. However, in such a case, the lamp may be very expensive so that it may be difficult to use this type of lamp as a heat source due to its cost effect on the overall price of the equipment.
In a heating manner using a resistance heater as a heat source, it may be difficult to instantaneously control heat transmission and the temperature of the heat source may be limited to be around the temperature to which a substrate should be heated. Thus, in such a case, it is difficult to secure a stable temperature due to an overshoot of the temperature. Further, from a microscopic point of view, there may be portions of a substrate that may be in contact and may not be in contact with the mounting table, thereby inducing differences in heat transmission therebetween. Thus, in this case, it is difficult to secure a temperature uniformity due to the differences of heat transmission, and as a result, a warpage of the substrate may easily occur. Therefore, it is difficult to achieve a rapid heating of the substrate.
It is, therefore, an object of some embodiments in the present disclosure to provide a substrate heating apparatus and a substrate heating method capable of rapidly raising a temperature as well as securing a stable and uniform in-surface temperature of a substrate without increasing equipment cost.
It is another object of some embodiments of the present disclosure to provide a substrate processing system performing a process including a heat treatment on the substrate by using a substrate heating apparatus.
In accordance with a first aspect of the present disclosure, a substrate heating apparatus is provided. The substrate heating apparatus includes a container configured to be maintained in a depressurized state; and a substrate mounting table having a plurality of substrate support pins on its upper surface. The substrate mounting table is configured to mount a substrate while providing a gap between the upper surface of the substrate mounting table and the substrate. The substrate heating apparatus further includes a heater that is configured to heat the substrate through the substrate mounting table; a pressure regulator configured to regulate a pressure in the container; a temperature controller configured to control an output of the heater so as to control a temperature of the substrate mounting table; and a pressure controller configured to control the pressure regulator so as to control the pressure in the container. The pressure controller controls the pressure in the container to a first pressure under which heat transmission by gas is possible when the substrate is mounted on the substrate mounting table, and to a second pressure under which there is substantially no heat transmission by gas when a temperature of the substrate reaches a predetermined temperature.
In one embodiment of the present disclosure, the pressure regulator includes a regulated pressure gas supply device configured to introduce gas at a regulated pressure into the container, an exhaust device configured to exhaust gas from the container, a flow controller configured to control a supply of the gas at a regulated pressure into the container, and a pressure control valve configured to control an exhaust of the container.
Also, the first pressure may be 1 Torr or higher. Further, the second pressure may be 100 mTorr or lower.
The substrate support pin may be configured to be height variable and a distance between a lower surface of the substrate and the upper surface of the substrate mounting table may be varied by adjusting the height of the substrate support pin. In this case, the substrate support pin may have a screw portion being screw-coupled to the substrate mounting table and the distance between the lower surface of the substrate and the upper surface of the substrate mounting table may be varied by rotating the substrate support pin.
Also, a plurality of substrate mounting tables may be provided so that a plurality of substrates may be heated in batches.
In accordance with a second aspect of the present disclosure, a substrate heating method is provided. The substrate heating method includes mounting a substrate on a substrate mounting table having a plurality of substrate support pins on its upper surface in a container maintained in a depressurized state while providing a gap between the upper surface of the substrate mounting table and the substrate; and heating the substrate through a heater that heats the substrate mounting table. A gas pressure in the container is controlled to a first pressure under which heat transmission by gas is possible so as to raise a temperature of the substrate when the substrate is mounted on the substrate mounting table, and the gas pressure in the container is controlled to a second pressure under which there is substantially no heat transmission by gas so as to maintain the temperature of the substrate at a predetermined temperature when the temperature of the substrate reaches the predetermined temperature.
In one embodiment of the present disclosure, the first pressure may be 1 Torr or higher. Also, the second pressure may be 100 mTorr or lower.
Further, a distance between a lower surface of the substrate and the upper surface of the substrate mounting table may be varied by adjusting a height of the substrate support pin.
In accordance with a third aspect of the present disclosure, a substrate processing system is provided. The substrate processing system includes a plurality of processing chambers configured to process a substrate in a depressurized atmosphere; a substrate heating apparatus configured to accommodate the substrate to be processed in the processing chamber and heat the substrate in a depressurized atmosphere before transferring the substrate to the processing chamber; a preliminary vacuum chamber configured to accommodate the substrate to be processed and maintain the substrate in a depressurized atmosphere before transferring the substrate to the processing chamber; and a common transfer chamber configured to be coupled with the plurality of processing chambers, the heating apparatus, and the preliminary vacuum chamber and to have a substrate transfer apparatus for transferring the substrate between the preliminary vacuum chamber and the plurality of processing chambers, the common transfer chamber maintained in a depressurized atmosphere. The substrate is transferred from the preliminary vacuum chamber to the heating apparatus by the substrate transfer apparatus so as to be pre-heated, and the pre-heated substrate is transferred to one of the processing chambers to perform a predetermined process.
In accordance with some embodiments of the present disclosure, upon raising a temperature of a substrate, the substrate is heated through heat transmission by gas by raising the pressure in the container while the substrate is separated from the upper surface of the substrate mounting table. Further, upon maintaining the temperature of the substrate, the pressure in the container is controlled to a pressure under which there is substantially no heat transmission by gas. As such, an in-plane temperature uniformity of the substrate can be secured as well as the temperature thereof can be rapidly raised. Also, without causing an overshoot, the substrate can be maintained at the predetermined temperature with high temperature stability. Also, the substrate may be heated up by a resistance heater, thereby avoiding an increase in equipment cost due to the use of lamp heating.
Embodiments will now be described in detail with reference to the accompanying drawings. In the accompanying drawings, the same or corresponding parts are given the same reference numerals.
Referring to
As shown in
In this embodiment, the common transfer chamber 10, the pre-heating chamber 20, and the processing chambers 30a and 30b are made of vacuum chambers and maintained in a predetermined depressurized atmosphere. The load lock chamber 40 serving as a preliminary vacuum chamber is configured such that it interchanges the substrate G between the substrate accommodating container (not shown) arranged on an atmospheric side and the common transfer chamber 10 maintained in a vacuum. The load lock chamber 40 is also configured such that it is switchable between an air atmosphere and a depressurized atmosphere.
The substrate processing system 1 is configured to mount and process a plurality of sheets, for example, three sheets of the substrates G in a horizontal direction perpendicular to a height direction. The plurality of sheets of the substrate G are carried in the load lock chamber 40 from the outer substrate accommodating container through the gate valve 64 by a transfer apparatus (not shown) arranged on an atmospheric side of the container. The carried-in substrates G are sequentially transferred from the load lock chamber 40 to the common transfer chamber 10 through the gate valve 63, from the common transfer chamber 10 to the pre-heating chamber 20 through the gate valve 61, and from the pre-heating chamber 20 to the processing chamber 30a or 30b through the gate valve 62a or 62b. The processed substrates G in the processing chamber 30a or 30b are sequentially transferred from the processing chamber 30a or 30b to the common transfer chamber 10 through the gate valve 62a or 62b and then from the common transfer chamber 10 to the load lock chamber 40 through the gate value 63. Thereafter, the processed substrates G are removed from the load lock chamber 40. Also, in this embodiment, the processing chambers 30a and 30b perform the same film forming process, but in some embodiments they may perform different film forming processes. For example, the processing chamber 30a may perform a first film forming process and then the processing chamber 30b may consecutively perform a second film forming process.
The substrate transfer apparatus 50 is configured to transfer a plurality of sheets, for example, three sheets of the substrates G in batches between the common transfer chamber 10 and the pre-heating chamber 20, and between the processing chambers 30a and 30b and the load lock chamber 40. As shown in
Respective parts of the substrate processing system 1 are controlled by a control unit 70 (e.g., a computer). The control unit 70 may include a process controller 71 provided with a microprocessor. A user interface 72 and a memory unit 73 are connected to the process controller 71. The user interface 72 may be made of a keyboard for enabling an operator to input commands for managing the substrate processing system 1, and a display for visualizing and displaying operating conditions of the substrate processing system 1. The memory unit 73 may store a control program for realizing processes to be performed in the substrate processing system 1 under the control of the process controller 71, or a program or instructions for directing the substrate processing system 1 to perform processes depending upon process conditions. The memory unit 73 may include a memory medium. The program or instructions may be stored in the memory medium. The memory medium may include a hard disk, a semiconductor memory, or a portable medium, for example, a CD-ROM (compact disc read only memory), a DVD (digital versatile disc), or a flash memory. In response to instructions from the user interface 72, the program and/or instructions are read out from the memory unit 73 and executed by the process controller 71, thereby performing a desired process in the substrate processing system 1 under the control of the process controller 71.
In the substrate processing system 1 having such a configuration, the gate valve 64 is opened first and then a plurality of sheets, e.g., three sheets, of substrates G to be processed are carried in the load lock chamber 40 (having an atmosphere of air) by a substrate transfer apparatus (not shown) arranged on an atmospheric side. The gate valve 64 is closed to depressurize the atmosphere in the load lock chamber 40. And then, the gate valve 63 is opened and the substrate support arms 51a, 51b, and 51c of the substrate transfer apparatus 50 are extended in batches to the load lock chamber 40, thereby receiving the non-processed substrates G which were carried in the load lock chamber 40. Afterwards, the substrate support arms 51a, 51b, and 51c of the substrate transfer apparatus 50 are retracted into the common transfer chamber 10 and then the gate valve 63 is closed. Subsequently, the base member 52 of the substrate transfer apparatus 50 is rotated to direct the substrate support arms 51a, 51b, and 51c to face the pre-heating chamber 20. And then, the gate valve 61 is opened and the substrate support arms 51a, 51b, and 51c are extended to the pre-heating chamber 20, thereby transferring the non-processed substrates G to the pre-heating chamber 20. Thereafter, the substrate support arms 51a, 51b, and 51c are retracted into the common transfer chamber 10, the gate value 61 is closed, and then a pre-heating of the substrates G is initiated in the pre-heating chamber 20. When the pre-heating is terminated, the gate valve 61 is opened and the substrate support arms 51a, 51b, and 51c are extended to the pre-heating chamber 20, thereby receiving the substrates G for which pre-heating is completed. Thereafter, the substrate support arms 51a, 51b, and 51c are retracted into the common transfer chamber 10 and the gate valve 61 is closed. And then, the base member 52 is rotated to direct the substrate support arms 51a, 51b, and 51c to face the processing chamber 30a or 30b. After that, the gate valve 62a or 62b is opened and the substrate support arms 51a, 51b, and 51c are extended to the processing chamber 30a or 30b, thereby transferring the substrates G for which pre-heating was completed to the processing chamber 30a or 30b. Consequently, the substrate support arms 51a, 51b, and 51c are retracted into the common transfer chamber 10, the gate valve 62a or 62b is closed, and then a process in the processing chamber 30a or 30b is initiated. When the process is terminated, the gate valve 62a or 62b is opened and the substrate support arms 51a, 51b, and 51c are extended to the processing chamber 30a or 30b, thereby receiving the processed substrates G. Continuously, the substrate support arms 51a, 51b, and 51c are retracted into the common transfer chamber 10 and the gate valve 62a or 62b is closed. Subsequently, the base member 52 is rotated to direct the substrate support arms 51a, 51b, and 51c to face the load lock chamber 40. And then, the gate valve 63 is opened and the substrate support arms 51a, 51b, and 51c are extended to the load lock chamber 40, thereby transferring the processed substrates G to the load lock chamber 40. Afterwards, the substrate support arms 51a, 51b, and 51c are retracted into the common transfer chamber 10, the gate valve 63 is closed, and then the inside of the load lock chamber 40 is changed to an atmosphere of air. Thereafter, the gate valve 64 is opened to remove the processed substrates G from the load lock chamber 40 by the substrate transfer apparatus (not shown) arranged on the atmospheric side.
The pre-heating chamber 20 (e.g., a substrate heating apparatus) will be described in detail.
The pre-heating chamber 20 may include a container 81. There is provided an opening 82 on a sidewall of the container 81 and the opening 82 can communicate with the common transfer chamber 10 maintained in a vacuum. The opening 82 may be opened and closed by the gate valve 61.
In the container 81, three substrate mounting devices 84a, 84b, and 84c are disposed in a vertical direction at regular intervals so as to mount and heat the three sheets of the substrates G.
The respective substrate mounting devices 84a, 84b, and 84c have a plane having a rectangular shape corresponding to the substrate G. Each of the substrate mounting devices 84a, 84b, and 84c is provided with a substrate mounting table 86 made of metal, where the substrate G is to be mounted. The substrate mounting table 86 is divided into two parts in a horizontal direction. A heater 87 is disposed between the two divided parts of the substrate mounting table 86. A thickness of each divided part may have a thickness of, for example, 15 mm, such that the substrate mounting table 86 will not warp due to heat from the heater 87. A plurality of substrate support pins 86a are disposed on the upper surface of the substrate mounting table 86 so that the substrate G is mounted separately from the upper surface of the substrate mounting table 86. As shown in
The heater 87 disposed on the substrate mounting table 86 is connected to a heater power supply 101. The heater power supply 101 feeds power to the heater 87 and then the heater 87 emits heat, thereby heating up the substrate G on the substrate mounting table 86 to a predetermined temperature. A thermocouple 102 may be embedded in close proximity to the upper surface of the substrate mounting table 86. The thermocouple 102 is configured to send a signal to a heater controller 103. The heater controller 103 is configured to transmit a command to the heater power supply 101 in response to the signal from the thermocouple 102, thereby controlling the heating of the heater 87. In this way, the heater controller 103 controls a temperature of the substrate mounting table 86 to the predetermined temperature.
The substrate mounting table 86 of each substrate mounting device 84a, 84b, or 84c is coupled through a connection member 89 to a plurality of frames 90 which are vertically elongated. The frames 90 are disposed on a lower portion of the container 81.
In the respective substrate mounting devices 84a, 84b, and 84c, a pair of comb-shaped substrate elevating members 88 are mounted and disposed on both long-side ends of the upper surface of the substrate mounting table 86, to thereby form a part thereof. The pair of substrate elevating members 88 are configured to support and elevate the substrate G. An upper surface of the substrate elevating member 88 and the upper surface of the substrate mounting table 86 form a plane on the same height level, cooperatively. In this embodiment, the substrate mounting table 86 is made of metal, but ceramics may be used instead of the metal.
As shown in
A gas introducing hole 111 may be formed on a lower wall of the container 81. A gas supply line 112 is coupled to the gas introducing hole 111. A regulated pressure gas supply source 113 is coupled to the gas supply line 112. On the gas supply line 112, there are provided a mass flow controller 114 serving as a flow controller for controlling gas flow and opening/closing valves 115 arranged on both sides of the mass flow controller 114. A gas at a regulated pressure, such as Ar gas, N2 gas and the like, is supplied from the regulated pressure gas supply source 113 to the container 81 through the gas supply line 112.
An exhaust hole 121 is disposed on the ceiling of the container 81 so as to exhaust the inside thereof. An exhaust line 122 is coupled to the exhaust hole 121. An automatic pressure control (APC) valve 123 and an exhaust device 124 are disposed on the exhaust line 122. While a pressure in the container 81 is controlled by the APC valve 123, the container 81 is exhausted by the exhaust device 124.
A pressure gauge 131 may be disposed in the container 81 to detect the pressure therein. A detection value of the pressure gauge 131 is outputted to a pressure controller 132. The pressure controller 132 is configured to send a control signal to the mass flow controller 114, the opening/closing valves 115, and the APC valve 123 so that it controls the exhaust and the supply of a gas at a regulated pressure, thereby depressurizing the container 81.
Also, the heater controller 103 and the pressure controller 132 are configured to be controlled by the control unit 70 which controls the whole operation of the substrate processing system 1.
In the pre-heating chamber 20 having such a configuration, the heater controller 103 is configured to control the heater power supply 101 to heat up the substrate mounting table 86 of the respective substrate mounting device 84a, 84b, and 84c to a predetermined temperature. Thereafter, the gate valve 61 is opened to carry in the substrates G supported by the substrate support arms 51a, 51b, and 51c of the substrate transfer apparatus 50 from the opening 82.
And then, the substrate elevating members 88 of the respective substrate mounting devices 84a, 84b, and 84c are elevated by the cylinder devices 97 to receive the substrates G thereon from the substrate support arms 51a, 51b, and 51c. Subsequently, the substrate support arms 51a, 51b, and 51c of the substrate transfer apparatus 50 are retracted into the common transfer chamber 10 and the gate valve 61 is closed. Afterwards, the substrate elevating members 88 supporting the substrates G descend toward the substrate mounting tables 86 to mount the substrates G on the substrate supporting pins 86a. In this manner, the substrates G being maintained at room temperature are heated up by the substrate mounting tables 86.
After the gate valve 61 is closed, along with the mounting operation of the substrates G, the mass flow controller 114 is controlled by the pressure controller 132 so that the gas at a regulated pressure is supplied from the regulated pressure gas supply source 113 to the container 81. Thus, the pressure in the container 81 is controlled to a first pressure P1 under which heat transmission by gas is possible. The first pressure P1 may be over 1 Torr, preferably over 3 Torr, and more preferably from 10 to 20 Torr, for example, 10 Torr.
At this time, a gap of a distance D is provided between the lower surface of the substrate G and the upper surface of the substrate mounting table 86 by the substrate support pins 86a and the gas pressure is over 1 Torr. Therefore, the substrate G is relatively rapidly heated up by heat transmission of the gas existing in the gap in addition to radiant heat from the substrate mounting table 86. If the substrate G is directly mounted on the substrate mounting table 86, heat transmission to portions of the substrate G directly in contact with the substrate mounting table 86 may be different from heat transmission to the remaining portions of the substrate G not in contact therewith due to the microscopic unevenness on the surface of the substrate mounting table 86. Therefore, it may be difficult to uniformly heat up the substrate G. On the contrary, by providing the gap between the lower surface of the substrate G and the upper surface of the substrate mounting table 86, heat transmission by gas is uniformly performed on the whole surface of the substrate G, thereby uniformly raising a temperature of the substrate G.
When the temperature of the substrate G reaches a predetermined temperature, the pressure in the container 81 is depressurized up to a second pressure under which there is substantially no heat transmission by gas. The second pressure is below 100 mTorr, preferably 1 to 100 mTorr. For example, the pressure in the container 81 is depressurized up to 100 mTorr under which there is substantially no heat transmission by gas, thereby maintaining the substrate G at the predetermined temperature. At this time, if a temperature of the upper surface of the substrate mounting table 86 is T2, a predetermined temperature T1 of the substrate G may be expressed as T1=T2−ΔT so that T1 is lower than T2 by ΔT. For example, ΔT may be set for 20 to 30° C. As such, by depressurizing the pressure in the container 81 up to a pressure under which there is substantially no heat transmission by gas, it becomes possible to maintain the substrate G at the predetermined temperature T1 while preserving a uniform temperature distribution without causing an overshoot.
That is, upon raising a temperature, the substrate G is heated up through heat transmission by gas by raising the pressure in the container 81 while the substrate G is separated from the upper surface of the substrate mounting table 86. Further, upon maintaining the temperature, the pressure in the container 81 is controlled to a pressure under which there is substantially no heat transmission by gas. As such, an in-plane temperature uniformity of the substrate G is secured while the temperature thereof is rapidly raised. Also, without causing the overshoot, the substrate G is maintained at the predetermined temperature T1 having high temperature stability.
Further, the substrate G is heated up by the heater 87 of a resistance heating type such that it may avoid the increase of equipment cost due to the use of lamp heating.
A temperature profile of the substrate G during the above described process is shown in
During the heating process of the substrate G, a temperature of the substrate G in some embodiments may not be measured directly such that a relationship is obtained between the temperature T2 of the substrate mounting table 86 and the temperature T1 of the substrate G in accordance with the first pressure P1, the second pressure P2, and the distance D of the gap between the lower surface of the substrate G and the upper surface of the substrate mounting table 86. Further, the temperature T2 of the substrate mounting table 86 for obtaining the temperature T1 of the substrate G is set in advance. Furthermore, since a timing transmitted from the first pressure P1 to the second pressure P2 may not be obtained from the actual temperature of the substrate G, in some embodiments a time required for a pressure transition is obtained in advance in accordance with the first pressure P1, the second pressure P2, and the distance D of the gap between the lower surface of the substrate G and the upper surface of the substrate mounting table 86. And then, the pressure transition should be taken when the time required for such a pressure transition has passed.
As such, by depressurizing the pressure in the container 81, the temperature of the substrate G can be maintained at the predetermined temperature such that it is possible to form a film in the approximate same condition even though a time from inserting and receiving the substrate G into and from the pre-heating chamber 20 varies due to transfer condition, etc. depending on whether the processing chamber is the chamber 30a or the chamber 30b.
While some embodiments have been described, various variations and modifications may be made without being limited to the foregoing embodiments. For example, the substrate processing system for transferring and processing three sheets of substrates in batches has been described, but one sheet of substrate and/or a plurality of sheets, other than three sheets, of substrates may be transferred and processed in batches. Also, the substrate processing system is not limited to
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel apparatus, method and system described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications which would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-015600 | Jan 2010 | JP | national |
